| Abstract No. |
Author(s) |
Title |
Abstract |
Suggested Session (click here to order table by session) |
Comment |
Contact email |
| 1 |
Lasukov V.V., Rozhkova S.V. |
Radioactive decay of Lemaître’s atom |
The paper studies a quantum theory of the early Universe with a negative cosmological constant. A gravitational analog of the non stationary perturbation theory is developed within which the production of the scalar-field massive quanta by gravitational atoms is studied. |
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
|
lav_8@list.ru |
| 2 |
Lasukov V.V. |
Dark matter and dark energy of the Universe |
It is shown that the incorporation of the Logunov coupling equations results in a nonzero Hamiltonian, which allows the problem of time of quantum gravitation theory to be solved outside the framework of traditional approaches. The quantum origin of the Universe due to a positive cosmological constant is studied. The paper advances new theoretical views a fundamental principle of periodicity of superspace and quantum geometrodynamics with a nonzero Hamiltonian. The prediction of an observable value of a cosmological constant is distinguishable from existing knowledge in principle. A possibility of existing spheres filled with a uniform constant scalar field in the Universe is shown. These spheres can act as dark matter and can be responsible for a decreasing behavior of the rotational curved galaxies observed. |
Astroparticle Physics |
|
lav_8@list.ru |
| 3 |
Kevin Kroeninger, Iris Abt, Allen Caldwell, Manuela Jelen, Daniel Lenz, Jing Liu, Xiang Liu, Bela Majorovits, Jens Schubert |
The GERmanium Detector Array, GERDA |
Neutrinoless double beta-decay is a rare, second order weak process which is predicted to occur if the neutrino is a Majorana particle. The observation of this process would reveal the nature of the neutrino. Its half-life would also give information about the absolute neutrino mass scale and the neutrino mass hierarchy.
The most stringent limits on the half-life of neutrinoless double beta-decay come from experiments based on the germanium isotope
Ge-76. The lower limits derived by the Heidelberg-Moscow and IGEX collaborations are 1.9e25 y and 1.6e25 y, respectively. A claim of discovery was made by parts of the
Heidelberg-Moscow collaboration. The sensitivity of these experiments was limited by the amount of background encountered which was dominated by gamma-radiation.
The GERmanium Detector Array, GERDA, is a new double beta-decay experiment which is currently under construction in the INFN Gran
Sasso National Laboratory, Italy. Its main feature is to operate bare germanium detectors directly in a buffer of high-purity argon which is used as a cooling medium and shield against external gamma-radiation simultaneously. The aim of the experiment is to verify or refute the recent claim of discovery and, in a second phase,
to achieve a background level two orders of magnitude below that of recent experiments. For this background level and an expected exposure
of 100 kg years GERDA will be sensitive to a half-life of 1.4e26 y, corresponding to an effective Majorana neutrino mass of about 200 meV depending on model calculations.
Several techniques to identify background events are implemented in the design of GERDA, such as the usage of segmented germanium detectors
and the analysis of the time structure of the detector response. The results of test experiments show the feasibility of these techniques. Accompanying Monte Carlo simulations are in good agreement with the data and can thus reliably predict the background estimate for GERDA.
|
Neutrino Physics |
|
kroening@mppmu.mpg.de |
| 4 |
Mohammad Saleem and Mujahid Kamran, Theory Group, Department of Physics, Punjab University, Lahore. PAKISTAN. |
Can material particles of zero rest mass exist in nature? |
The presence or absence of neutrinos of zero rest mass plays a significant role in the development of High Energy Physics. It is shown in this paper that causality precludes material particles, and hence neutrinos, of zero rest mass. This will require a major change in theories of High Energy Physics. |
Neutrino Physics |
|
dmsdmsaleem@yahoo.com |
| 5 |
A. Bodek, H. Budd, S. Avvakumov, R. Bradford |
Duality Based Vector and Axial Form Factors- Improved Modeling of Quasielastic Neutrino Cross Sections at all Energies |
We present a re-analysis of all existing electron and neutrino elastic and quasielastic
scattering data on nucleons. By using theoretical constraints from Quark-Hadron
duality, we obtain new precise parametrizations of vector and axial nucleon form
factors. These new parametrizations are used to improve the predictions for quasielastic
neutrino-nucleon cross sections of GeV neutrinos, thus reducing
the errors on neutrino oscillations parameters extracted from present and future
neutrino oscillations experiments. |
Neutrino Physics |
|
bodek@pas.rochester.edu |
| 6 |
A. Bodek, U. K. Yang |
Modeling of Inelastic Neutrino Cross Sections at all Energies |
We also present updated improvements in the
Bodek-Yang model for inelastic neutrino, electron and muon scattering on nucleons,
with a combined analysis of all neutrino, muon and electron scattering experiments at
all energies. |
Neutrino Physics |
|
bodek@pas.rochester.edu |
| 7 |
A. K. Monin, A. V. Zayakin |
Induced Schwinger Process at Non-Zero Temperature |
Induced process of pair production by an external field is
studied at finite temperature. The width of the Thirring meson is
calculated within the framework of the Schwinger approach. This
quantity appears to be non-perturbative in the external field
strength, that is, its field strength dependence exhibits an
essential non-analyticity in the weak field limit. The decay rate of
the meson at arbitrary temperatures, being expressed exactly in
terms of the Matsubara frequencies sum, is given simple approximate
estimates for both high- and low-temperature asymptotics. |
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
|
zayakin@itep.ru |
| 8 |
Q. Shafi |
Realistic Models of Inflation |
Realistic models of inflation are expected to be closely related to new physics beyond the standard model. We explore such models including
some which are closely related to neutrino
oscillations . |
Astroparticle Physics |
In order to finalize my summer plans it would be very helpful if I could get an early response. |
shafi@bartol.udel.edu |
| 9 |
Y H Huseynaliyev, M K Suleymanov, E U Khan, A Kravchakova, S Vokal |
Search for a signal on intermediate baryon systems formation in hadron-nuclear and nuclear-nuclear interactions at high energies |
We have analyzed the behavior of different characteristics of hadron-nuclear and nuclear-nuclear interactions as a function of centrality to get a signal on formation of intermediate baryon systems. We observed that these data demonstrate the regime change and saturation. At low energy is existing some structure on the angular distributions of slow particles emitted in these interactions. We have believed that the structure could be connected with formation and decay of the percolation cluster. With increasing the mass of colliding nuclei the structure becomes weakly and almost disappears. This result shows that the number of secondary internuclear interactions increases with increasing the mass of the colliding nuclei. The latter could be a reason of the disintegration of any intermediate formations as well as clusters, which decrease their influence on the angular distribution of the emitted particles. |
High-Energy Nuclear Physics |
|
yashar_huseynaliyev@comsats.edu.pk |
| 10 |
Asish Satpathy |
CMS Silicon Tracker - Overview and Status |
The CMS experiment at the LHC features the largest Silicon Strip Detector ever built. The impact of the operating conditions and physics requirements on the design choices of the CMS Silicon Tracker will be reviewed. The readiness of the Silicon Tracker for the scheduled CMS pilot run in November 2007 will be presented. |
Detectors and Data Handling |
I would need about 30 minutes for this talk. |
asish.satpathy@ucr.edu |
| 11 |
D.Fargion |
UHECR and neutrino Showering above and below the Earth |
The UHECR Ultra High Energy Cosmic Ray may airshower at the horizons with a very peculiar splitting signature due to geomagnetic fields.
The same induced Neutrino Astronomy might be born by upward horizontal airshowers due to antineutrino electron Glashow resonance and-or by Tau Neutrino Earth Skimming Air showers. The latter are mostly GZK garanteed and oscillated neutrinos at EeV energy. At different altitude the rate and signature is different. The possibility to use this new filter in astrophysics is already at hand. HESS telescope is tracking HECR compositions. Magic is looking for Horizontal Tau Air Showers. AUGER is looking at the Ande shadows for any Neutrino Showering to be found just beyond the corner. |
Neutrino Physics |
"The Horizontal Air-Shower Physics regards UHECR, Neutrino and SUSY physics Beyond the SM" |
daniele.fargion@roma1.infn.it |
| 12 |
D.Fargion |
Surprises by SUSY in the Sky with Showers |
The SUSY signals might be found in LHC in next few years. However novel signals of SUSY must be found
in inderground detectors but also
in UHECR either at the horizons or in Upward air-showers. The SUSY lightest candidate, the Neutralino, may compete with Neutrino by air-showering via s-electron resonances. Moreover Gluinos might also play a role. We shall show the SUSY unexpected novel imprint in present and future array detectors, in particular showering in the Sky. |
Physics Beyond the Standard Model |
"The UHE SUSY signals are complementary to UHE neutrino Astronomy, but in some way, in wider forms." |
daniele.fargion@roma1.infn.it |
| 13 |
BES Collaboration |
Recent Charmnium and Charm physics results from BES |
By analyzing the R values measured at 68 energy points in the energy region between 3.650 and 3.872 GeV, we have precisely measured the mass, the total width, the leptonic width and the leptonic decay branching fraction of the psi(3770). We have also measured R(uds) for the continuum light hadron production in the region from 3.650 to 3.872 GeV [hep-ex/0612056]. Based on the data sample of 33 pb(-1) collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, the absolute branching fractions for the semileptonic decays are measured [hep-ex/0610019, hep-ex/0610020].
Using 14 million psi(2S) events accumulated at the BESII detector, a Covariant Helicity Amplitude Analysis is performed for psi(2S) -> pi+pi-J/psi. The pi+pi- mass spectrum, suggests sigma production in this process and the results are consistent with the existence of the sigma. The sigma pole position is determined [hep-ex/0610023]. We report first measurements of branching fractions or upper limits for psi(2S) radiative decays [hep-ex/0612016], and report the measurements for psi(2S) Baryon-antibaryon pairs decays[hep-ex/0610079]
|
Flavour Physics and CP Violation |
|
chenjc@mail.ihep.ac.cn |
| 14 |
BES Collaboration |
Recent Charm and Charmonium physics results from BES |
By analyzing the R values measured at 68 energy points in the energy region between 3.650 and 3.872 GeV, we have precisely measured the mass, the total width, the leptonic width and the leptonic decay branching fraction of the psi(3770). We have also measured R(uds) for the continuum light hadron production in the region from 3.650 to 3.872 GeV [hep-ex/0612056]. Based on the data sample of 33 pb(-1) collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, the absolute branching fractions for the semileptonic decays are measured [hep-ex/0610019, hep-ex/0610020].
Using 14 million psi(2S) events accumulated at the BESII detector, a Covariant Helicity Amplitude Analysis is performed for psi(2S) -> pi+pi-J/psi. The pi+pi- mass spectrum, suggests sigma production in this process and the results are consistent with the existence of the sigma. The sigma pole position is determined [hep-ex/0610023]. We report first measurements of branching fractions or upper limits for psi(2S) radiative decays [hep-ex/0612016], and report the measurements for psi(2S) Baryon-antibaryon pairs decays[hep-ex/0610079]
|
Flavour Physics and CP Violation |
|
chenjc@mail.ihep.ac.cn |
| 15 |
BES Collaboration |
Recent Charm and Charmonium physics results from BES |
By analyzing the R values measured at 68 energy
points in the energy region between 3.650 and 3.872
GeV, we have precisely measured the mass, the total
width, the leptonic width and the leptonic decay
branching fraction of the psi(3770). We have also
measured R(uds) for the continuum light hadron
production in the region from 3.650 to 3.872 GeV
[hep-ex/0612056]. Based on the data sample of 33
pb(-1) collected at and around 3.773 GeV with the
BES-II detector at the BEPC collider, the absolute
branching fractions for the semileptonic decays are
measured [hep-ex/0610019, hep-ex/0610020].
Using 14 million psi(2S) events accumulated at the
BESII detector, a Covariant Helicity Amplitude
Analysis is performed for psi(2S) -> pi+pi-J/psi.
The pi+pi- mass spectrum, suggests sigma production
in this process and the results are consistent with
the existence of the sigma. The sigma pole position
is determined [hep-ex/0610023]. We report first
measurements of branching fractions or upper limits
for psi(2S) radiative decays [hep-ex/0612016], and
report the measurements for psi(2S) Baryon-antibaryon
pairs decays[hep-ex/0610079]
|
Flavour Physics and CP Violation |
|
chenjc@mail.ihep.ac.cn |
| 16 |
Pramod K. Singh, Anil K. Tiwari, Anil K. Shrivastava, Ambika Singh and Laxmi Tripathi |
SOLAR WIND STREAMS AND THEIR IMPACT ON COSMIC RAY INTENSITY DECREASES |
Long durations solar wind streams of very high velocity and long duration were observed during the year 2003, the declining phase of solar cycle 23.In this year large number of streams were found to be anomalous.Eleven events of High Speed Solar Wind Streams and associated cosmic ray intensity decreases (Fd)were observed in the year.It was found that during event time period plasma density,plasma temperature as well as interplanetary magnetic field component(B)increases with the solar wind plasma speed.Results will be discussed. |
Astroparticle Physics, Gravitational Waves and Cosmology |
nill |
tiwarianil_trs@rediffmail.com |
| 17 |
Rimoldi, A; Dell'Acqua, A; Gallas, M.; Di Simone, A; |
The Simulation suite for the ATLAS Experiment |
The commissioning phase for the ATLAS experiment, now in preparation of the switching on of the new LHC machine, is a challenge for every development since now performed. The simulation program is in this line, it is operational and running with full functionality within the ATLAS common framework Athena. The latest developments are towards an enhanced versatility, to cope with the increasing needs of developers and users, an easiness in use by a big community such as ATLAS reaching now more than 2000 potential users. Enphasis in this talk is towards the new functionality recently added, validation and production strategy as well as improved robustness and maintainability. |
Detectors and Data Handling |
|
adele.rimoldi@cern.ch |
| 18 |
Oliver J Rosten |
Invariant of the Generalized Polchinski Equation |
The Polchinski equation is a continuum version of Wilson's RG and, as such, describes how the effective action of scalar field theory changes with scale. The lowering of the scale corresponds to integrating out modes. The generalizations of the Polchinski equation that will be discussed correspond to generalizing the way in which high energy modes are integrated over or `blocked'. For a special choice of the blocking functional, it will be shown that it is possible to construct an infinite number of quantities which are invariant under the Exact RG flow. Remarkably, the relationship between these quantities and the Wilsonian effective action vertices can be inverted. From this, it will be shown how power corrections (which are intrinsically nonperturbative) systematically appear in the low energy effective action. |
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
|
orosten@stp.dias.ie |
| 19 |
SuperNEMO Collaboration |
The neutrinoless double beta decay experiment SuperNEMO |
SuperNEMO is a next-generation double beta decay
experiment based on the successful tracking
plus calorimetry technology of the NEMO-3
experiment currently running in the Modane
Underground Laboratory. Due to its unique
tracking and particle identification capabilities
the SuperNEMO experiment might not only be able
to discover neutrinoless double beta decay, but
also to determine the underlying physics
mechanism. Due to the separation of source and
detector, SuperNEMO can study a range of
isotopes such as 150Nd or 82Se.
The total isotope mass will be in the range
100-200 kg. With this isotope mass a sensitivity
to neutrino masses of about 50 meV can be
reached. Module construction is expected to
commence in 2009/2010.
The main challenges for the international R&D
project are source foil production, radiopurity,
calorimeter energy resolution and tracker
construction. A first version of the BiPo
detector used to measure source foil radiopurity
has been installed in the Canfranc Laboratory.
The current status of the SuperNEMO project will be presented. |
Neutrino Physics |
Also Astroparticle Physics. |
soldner@fnal.gov |
| 20 |
V. V. Dvoeglazov |
Antisymmetric Tensor Fields, 4-Vector Fields, Indefinite Metrics and Normlization |
On the basis of our recent modifications of the Dirac formalism we generalize the Bargmann-Wigner formalism for higher spins to be compatible
with other formalisms for bosons. Relations with dual electrodynamics, with the Ogievetskii-Polubarinov notoph and the Weinberg 2(2J+1) theory are
found. Next, we introduce the dual analogues of the Riemann tensor and derive corresponding dynamical equations in the Minkowski space. Relations
with the Marques-Spehler chiral gravity theory are discussed. The problem of indefinite metrics, particularly, in quantization of 4-vector fields is clarified.
|
Physics Beyond the Standard Model |
|
valeri@planck.reduaz.mx |
| 21 |
SHIN-SHAN YU |
CDF SEARCH FOR NEW PHYSICS WITH PHOTONS |
We present the results of several model-independent searches for new physics in
events containing high ET photons. Photons appear in many models such as SUSY,
Technicolor, Large Extra Dimensions and compositeness. Using 1-1.5 fb-1 of
data collected with the CDF II detector at the Fermilab Tevatron, we search
for anomalous production of events with one or two photons with other
objects, such as leptons, jets, missing Et. Methods to reject fake photons
will also be discussed.
|
Physics Beyond the Standard Model |
|
eikoyu@fnal.gov |
| 22 |
NEMO-3 Collaboration |
Search for neutrinoless double beta decay with NEMO-3 |
The NEMO-3 experiment located in the Modane Underground Laboratory (LSM)
is searching for neutrinoless double beta decay. The experiment
has been taking data since 2003 with a range of isotopes.
The main isotopes are ~ 7 kg of 100Mo and ~ 1 kg of 82Se.
Since no evidence for neutrinoless double beta decay has been found,
a 90% Confidence Level lower limit on the half-life of this process is derived.
From this we determine an upper limit on the effective Majorana neutrino
mass using nuclear matrix elements.
The data are also interpreted in terms of alternative models, such
as weak right-handed currents or Majoron emission.
In addition, NEMO-3 has performed precision measurements of the double beta
decay process with two neutrinos emitted in the final state.
Measurements of this process are important
for reducing the uncertainties on the nuclear matrix elements.
The most recent experimental results will be presented.
|
Neutrino Physics |
also Astroparticle |
soldner@fnal.gov |
| 23 |
B. Basu, S. Dhar and Subir Ghosh |
Geometric Phases in Noncommutative Phase Space |
We have studied particle motion in generalized forms of
noncommutative phase space, that simulate monopole and other
forms of Berry curvature, that can be identified as effective
internal magnetic fields, in coordinate and momentum space. The
Aharanov-Bohm effect and Aharanov- Casher effect have been considered in this form of phase
space, with operatorial structures of noncommutativity. Physical
significance of our results are also discussed. |
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
|
banasri@isical.ac.in |
| 24 |
Shulamit Moed |
Helicity of W Bosons in Top Quark Decays at CDF |
We present a measurement of the fraction of longitudinally and left-handed polarized W bosons, produced in top quark decays through an analysis of the cosine(theta*) distribution in ttbar candidate events using fully reconstructed lepton plus jets events. This analysis is based on a total integrated luminosity of about 2fb-1 recorded by the CDF detector using ppbar collisions at 1.96 TeV center-of-mass energy.
|
High-Energy Electroweak Physics |
|
moed@fnal.gov |
| 25 |
Double Chooz collaboration |
Status of the Double Chooz Reactor Experiment |
The Double Chooz project aims to make a
first measurement of the neutrino mixing angle
theta13 on a rapid timescale by installing
an improved detector system at the site of
the successful CHOOZ experiment, in France.
Construction of the Phase I far detector
begins this winter and should yield a factor
of 2-3 improvement on existing bounds before
2010. A second near detector will come online
after 2010 which will further strengthen and
improve upon this measurement. The design and
status of this project will be presented here.
|
Neutrino Physics |
|
steven.biller@physics.ox.ac.uk |
| 26 |
R M Brown, on behalf of the CMS ECAL Group |
The CMS Lead Tungstate Electromagnetic Calorimeter |
The CERN Large Hadron Collider will open a new regime in the exploration of fundamental interactions. Of central importance to these studies will be the precise measurement of high energy electrons and photons. The CMS experiment therefore incorporates a high resolution electromagnetic calorimeter comprising 76000 lead tungstate crystals, covering almost 4Pi. This detector must operate reliably for ten years in a very hostile environment. Achieving the required robustness and the design energy resolution of better than 0.5% above 100 GeV has proved a considerable challenge. An overview of the design and the status of construction and commissioning will be reported together with beam measurements, demonstrating that the design performance has been achieved. |
Detectors and Data Handling |
|
R.M.Brown@RL.AC.UK |
| 27 |
Xiao-Gang He, Jusak Tandean, German Valencia |
Sigma to p mu+ mu-: Standard Model or Light Pseudoscalar Higgs |
The HyperCP collaboration observed three events for the decay Sigma^+ -> p mu^+ mu^-. They suggested that new physics may be required to understand the implied decay rate and the observed M_{mumu} distribution. Motivated by this result, we re-examine this mode. First within the standard model, and then assuming there is a new particle.
Within the SM we find that Sigma^+ -> p mu^+ mu^- is long-distance dominated and its rate falls within the range suggested by the HyperCP measurement. We then examine the conditions under which the observation is consistent with a light Higgs boson and find an explicit example that satisfies all the constraints: the light pseudoscalar Higgs boson in the next-to-minimal supersymmetric standard model, the A_1^0. |
Flavour Physics and CP Violation |
|
valencia@iastate.edu |
| 28 |
German Valencia and Yili Wang |
A CP-odd observable in t t(bar) production at the LHC |
We study a CP-violating triple product correlation that occurs in the production of t\bar{t} pairs at the LHC. To estimate its possible size we consider a model with CP violation in the Higgs sector. We consider the H -> t \bar{t} decay channel as well as the gluon fusion process gg -> H -> t \bar{t}. The asymmetry in Higgs decay, normalized to the H -> t \bar{t} width, can reach the 6% percent level. In the gluon fusion process the corresponding normalized asymmetry is smaller by an order of magnitude. We present a crude estimate of this observable at the LHC. |
Physics Beyond the Standard Model |
Could be High energy electroweak physics also |
valencia@iastate.edu |
| 29 |
Jen-Chi Lee |
Surprises with string scattered from domain-wall at high energies |
In contrast to the common wisdom, we discover that, instead of the exponential fall-off of the form factors with Regge-pole structure, the high-energy scattering amplitudes of string scattered from Domain-wall behave like power-law with Regge-pole structure. This is to be compared with the well-known power-law fall-off form factors without Regge-pole structure of the D-instanton scatterings. This discovery makes Domain-wall scatterings an unique example of a hybrid of string and field theory scatterings. The calculation is done for bosonic string scatterings of arbitrary massive string states from D-24 brane. Moreover, we discover that the usual linear relations of high-energy string scattering amplitudes at each fixed mass level breaks down for the Domain-wall scatterings. This result gives a strong evidence that the existence of the infinite linear relations, or stringy symmetrie, of high-energy string scattering amplitudes is responsible for the softer, exponential fall-off high-energy string scatterings than the power-law fall-off field theory scatterings.
|
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
"Refs: hep-th/0610062,hep-th/0610219 and hep-th/0612059." |
jcclee@cc.nctu.edu.tw |
| 30 |
Cheng-Wei Chiang, Yu-Feng Zhou |
Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons |
Global fits to charmless B --> PP decays in the framework of flavor SU(3) symmetry are updated and improved without reference to the \sin2\beta measured from the charmonium decay modes. Fit results directly constrain the (\bar\rho,\bar\eta) vertex of the unitarity triangle, and are used to predict the branching ratios and CP asymmetries of all decay modes, including those of the B_s system. Different schemes of SU(3) breaking in decay amplitude sizes are analyzed. The major breaking effect between strangeness-conserving and strangeness-changing decays can be accounted for by including a ratio of decay constants in tree and color-suppressed amplitudes. The possibility of having a new physics contribution to K \pi decays is also examined from the data fitting point of view. |
Flavour Physics and CP Violation |
|
zhou@post.kek.jp |
| 31 |
Cheng-Wei Chiang, Yu-Feng Zhou |
Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons |
Global fits to charmless B --> PP decays in the framework of flavor SU(3) symmetry are updated and improved without reference to the \sin2\beta measured from the charmonium decay modes. Fit results directly constrain the (\bar\rho,\bar\eta) vertex of the unitarity triangle, and are used to predict the branching ratios and CP asymmetries of all decay modes, including those of the B_s system. Different schemes of SU(3) breaking in decay amplitude sizes are analyzed. The major breaking effect between strangeness-conserving and strangeness-changing decays can be accounted for by including a ratio of decay constants in tree and color-suppressed amplitudes. The possibility of having a new physics contribution to K \pi decays is also examined from the data fitting point of view. |
Flavour Physics and CP Violation |
Journal-ref: JHEP 0612 (2006) 027 |
zhou@post.kek.jp |
| 32 |
Cheng-Wei Chiang, Yu-Feng Zhou |
Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons |
Global fits to charmless B --> PP decays in the framework of flavor SU(3) symmetry are updated and improved without reference to the \sin2\beta measured from the charmonium decay modes. Fit results directly constrain the (\bar\rho,\bar\eta) vertex of the unitarity triangle, and are used to predict the branching ratios and CP asymmetries of all decay modes, including those of the B_s system. Different schemes of SU(3) breaking in decay amplitude sizes are analyzed. The major breaking effect between strangeness-conserving and strangeness-changing decays can be accounted for by including a ratio of decay constants in tree and color-suppressed amplitudes. The possibility of having a new physics contribution to K \pi decays is also examined from the data fitting point of view. |
Flavour Physics and CP Violation |
hep-ph/0609128. Journal-ref: JHEP 0612 (2006) 027 |
zhou@post.kek.jp |
| 33 |
Sebastian de Haro |
Bubbles of True Vacuum in M-Theory |
I will review recent progress in the holographic description of tunneling processes in M-theory, in particular the issue of bubble formation, which is crucial in various areas of cosmology such as inflationary scenarios. The talk is based on the series of papers hep-th/0606276, hep-th/0611315, hep-th/0701144. |
Non-Perturbative Field Theory, String Theory, Quantum Groups and Non-Commutative Geometry |
|
sebastian.deharo@kcl.ac.uk |
| 34 |
N.Armesto, L.Cunqueiro,C.Salgado and W.Xiang |
Medium Modified Fragmentation Functions |
We extend the Sudakov formalism from vacuum to opaque media by modifying
the splitting functions with the medium-induced gluon radiation spectrum.
We then solve DGLAP evolution equations in order to obtain the medium
modified fragmentation functions. The medium increses the branching
probability and thus accelerates the evolution. We will present some
examples at relevant LHC scales.
In this way, some of the limitations of previous attempts of MMFF based on
the use of the quenching weights are now superseeded.
As a phenomenological application, we compute the suppression of the
high pt yields in heavy-ion collisions by convoluting the obtained
fragmentation functions with the perturbative spectrum. This allows us to
obtain the value of the time averaged transport coefficient-- the quantity
encoding the medium properties -- which will be comparedwith that obtained
in other approaches neglecting the mediummodification of QCD evolution.
|
High-Energy Nuclear Physics |
|
leticia@fpaxp1.usc.es |
| 35 |
Bezrukov Fedor |
nuMSM and its experimental tests |
The nuMSM is the simple extenson of the Standard Model by three massive singlet neutrinos. It provides explanation for the neutrino masses, Dark Matter and baryon asymmetry of the Universe, providing also prediction for the scale of the active neutrino masses. In this talk we are going to discuss the possible outcome of the theory for particle physics experiments. |
Physics Beyond the Standard Model |
Neutrino physics session may be also ok. |
Fedor.Bezrukov@epfl.ch |
| 36 |
Maxim Dvornikov |
New approach to the description of neutrino oscillations in various external fields |
We examine neutrino flavor and spin-flavor oscillations in frames of the classical field theory approach. Neutrinos wave functions are considered to be first quantized fields. Neutrino oscillations in vacuum, in matter and in an external electromagnetic field are studied. On the basis of the exact solutions of the Dirac equation in various external fields we obtain the corresponding transition and survival probabilities. The obtained probabilities expressions are compared with the results of other methods for the description of neutrino oscillations. We also discuss the corrections to the leading terms in the probabilities expressions. |
Neutrino Physics |
"The talk is based on the following works: 1) M. Dvornikov, Phys.Lett.B 610 (2005) 262; hep-ph/0411101. 2) M. Dvornikov, Eur.Phys.J.C 47 (2006) 437; hep-ph/0601156. 3) M. Dvornikov, J. Maalampi, hep-ph/0701209." |
dvmaxim@cc.jyu.fi |
| 37 |
BHAVIN PATEL, AJAY KUMAR RAI , P.C.VINODKUMAR |
Masses and magnetic moments of heavy flavour baryons in Hyper central model |
Recently, there is a renewed interest in the magnetic moments and spectroscopy of heavy flavour baryons both experimentally and theoretically [1-9]. The description of baryons within the constituent quark models is an important task in hadron physics. Since the baryon is a three-body system, it is complicated compared to the two body meson system. Many of the constituent quark models have provided the masses of baryons and their magnetic moments correctly at the light flavour sector. However many of these models do not provide the form factors correctly that reproduces experimental data [1] and for this reason alternate schemes to describe the properties of baryons particularly in the heavy flavour sector are being attempted [1, 2].
Here, we employ the hyper central approach to study the three-body problem [1, 2], particularly the baryons constituting one or more charm and or beauty quarks. The confinement potential is assumed in the hyper central co-ordinates of the coulomb plus power potential form. It should be mentioned that, hyper central potential contains the effects of the three body force as it is suggested by lattice QCD calculations [8]. For the low-lying resonance states it is good approximation to simply take the space wave functions of the hyper Coulomb potential instead of the ones coming from the numerical solution of the linear plus Coulomb potentials with hyperfine interaction. Our computed results on the masses and magnetic moments of the charmed and beauty baryons computed under this scheme for different power indices starting from 0.5 to 2.0 will be presented [9].
References
[1] M. M. Giannini et. al, Eur. Phys. J.A 12, 447-452 (2001).
[2] E. Santopinto et. al , Eur. Phys. J.A 1, 307- 315 (1998).
[3] P. Avery et. al., CLEO collab. Phys. Rev. Lett. 75, 4364 (1995).
[4] D. Ebert et. al, Phys. Rev. D 72, 034026 (2005).
[5] W. M. Yao et. al, (PDG) Jour. Phys. G 33,1(2006).
[6] S. B. Athar et. al, [CLEO Collaboration], Phys. Rev. D 71 ,051101(2005).
[7] Eduarev Dela Cruz Burelo (CDF & Collaboration) Nucl. Phys. B (Proce. Suppl.) 156,244(2006).
[8] Gunnar S.Bali, Phys. Rep. 343 (2001) 1.
[9] Bhavin Patel et. al ‘Charmed and Beauty Baryon in hyper Central Model’
Proc. DAE-BRNS Symp. on Nucl. Phys. Vol. 51(2006)509-510.
|
Strong Interactions |
|
azadpatel2003@yahoo.co.in |
| 38 |
Mario Martinez (IFAE-Barcelona, CDF Collaboration) |
Inclusive Search for Squark/Gluino Production at CDF |
We present preliminary results on search for squarks and gluinos in proton-antiproton collisions at sqrt{s} = 1.96 TeV at Tevatron,
based on 1 fb-1 of data collected by the CDF experiment in Run II. The search is performed on events with multiple jets and large missing
transverse energy in the final state, within the framework of the Minimal
Supersimmetric Standard Model and assuming that the R-parity is conserved.
The measurement is compared to the Standard Model predictions and
limits on the gluino and squark masses are extracted.
|
Physics Beyond the Standard Model |
On behalf of the CDF Collaboration |
mmp@fnal.gov |
| 39 |
Mario Martinez (IFAE-Barcelona, CDF Collaboration) |
Measurement of the Inclusive Z+jet(s) Production Cross Section at CDF |
We present preliminary results on inclusive Z-boson plus jets production in pp-bar collisions at sqrt{s} = 1.96 TeV. The measurements are based on 1 fb-1 of data collected by the CDF experiment in Run II. The analysis is performed
in the context of studies on irreducible backgrounds in searches for new physics in
final states with jets and missing transverse energy. The measured cross sections are
compared to NLO pQCD predictions.
|
Strong Interactions |
on behalf of the CDF Collaboration |
mmp@fnal.gov |
| 40 |
M. Martinez (IFAE-Barcelona, CDF Collaboration) |
Measurement of the Inclusive Jet Cross Section using the k_T algorithm in pp-bar Collisions at sqrt{s} = 1.96 TeV with the CDF II Detector |
We report on measurements of the inclusive jet production cross section as a function of the
jet transverse momentum in pp-bar collisions at sqrt{s} = 1.96 TeV, using the k_T algorithm and a data sample corresponding to 1.0 fb^-1 collected with the Collider Detector at Fermilab in Run II. The measurements are carried out in five different jet rapidity regions with
|yjet| < 2.1 and transverse momentum in the range 54 < ptjet < 700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.
|
Strong Interactions |
on behalf of the CDF Collaboration |
mmp@fnal.gov |
| 41 |
Arnaud Belletoile for the Codalema colaboration |
radiodetection of UHECR with Codalema |
The CODALEMA experiments has been succesfully reinvestigating the radiodetection method of UHECR for few years. Since September 2006, it is under operation with a new setup at the Nancay Radio Observatory, France. It uses 16 broadband dipole antennas associated with 13 particle detectors generating the trigger and allowing the primary cosmic ray energy estimation. We will present the evidence for the radio detection of cosmic ray above 10^17 eV, based on an event by event analysis showing time and arrival direction coincidences between the two detectors arrays. The characteristics of the showers detected, like core position and lateral electric field dependence, will be presented. Finally, the correlation between the cosmic ray energy determined by the particle detectors and the electric field amplitude measured by the dipoles will be discussed. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
arnaud.belletoile@subatech.in2p3.fr |
| 42 |
A.B.Kaidalov, M.I.Vysotsky |
To the origin of the difference of FSI phases in $B\to\pi\pi$ and $B\to\rho\rho$ decays. |
The final state interactions (FSI) model in which soft rescattering of low mass
intermediate states dominates is
suggested. It explains why the strong interaction phases
are large in the
$B_d\to\pi\pi$ channel and are considerably smaller in the
$B_d\to\rho\rho$ one. Direct CP asymmetries of $B_d\to\pi\pi$
decays which are determined by FSI
phases are considered as well. |
Flavour Physics and CP Violation |
|
vysotsky@itep.ru |
| 43 |
Karel Kolar |
On factorization scheme suitable for MC event generators |
At the present time, many hard scattering processes at the parton level are calculated at the next-to-leading order (NLO) accuracy and the corresponding NLO cross-sections are being incorporated in current Monte-Carlo event generators. However, the construction of consistent NLO event generators requires, beside NLO matrix elements for the parton level hard processes and NLO parton distribution functions (PDF), also the generation of NLO parton showers, which simulate the scale dependence of PDF. However, the generation of NLO parton showers is much more complicated than the
generation of LO ones, and that is probably why the developed algorithm for the generation of NLO parton showers has so far not gained wider use. The complications in generating NLO parton showers are caused by some properties that
the NLO splitting functions have in the "standard" MS bar factorization scheme. Therefore, the complications could be avoided by the choice of a convenient factorization scheme. The most convenient factorization scheme for that
is the one in which all NLO splitting functions are equal to zero, because NLO parton showers are then formally identical to LO ones. Working in this factorization scheme, we thus obtain results at the NLO accuracy without changing
the procedure for generating parton showers. We must only transform parton level cross-sections and PDF from the "standard" MS bar factorization scheme to the one which we call "zero". Two important points for the construction of consistent NLO event generators in this way will be presented: the transformation of parton level cross-sections and PDF between factorization schemes and obtaining necessary parameters for the determination of the "zero" factorization scheme. |
Strong Interactions |
I would like to give a talk on the subject specified in the above Abstract |
kolark@fzu.cz |
| 44 |
Daniel de Florian, Rodolfo Sassot, Marco Stratmann |
Global analysis of fragmentation functions for pions and kaons
and their uncertainties |
We present new sets of pion and kaon fragmentation functions obtained in NLO
combined analyses of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and deep-inelastic
lepton-proton scattering with either pions or kaons identified in the final state.
At variance with all previous fits, the present analyses take into account data where hadrons of
different electrical charge are identified,
which allow to discriminate quark from anti-quark fragmentation functions without the need of
non trivial flavor symmetry assumptions.
The resulting sets are in good agreement with all data analyzed, which cover a much wider kinematical range than in previous fits.
An extensive use of the Lagrange multiplier technique is made in order to assess the uncertainties in the extraction of the fragmentation functions and the synergy from the complementary data sets in our global analysis. |
Strong Interactions |
hep-ph/0703242 |
sassot@df.uba.ar |
| 45 |
ZEUS Collaboration |
Measurement of prompt photons with associated jets in photoproduction at HERA |
The photoproduction of prompt photons, together with an accompanying jet, has been studied in ep collisions at a centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 77 pb-1. Cross
sections were measured for the transverse energy of the photon and the jet larger than 5 and 6 GeV, respectively. The differential gamma+jet cross sections were reconstructed as functions of the transverse energy, pseudorapidity and x(gamma)^obs, the fraction of the incoming photon momentum taken by the photon-jet system. Predictions based on
leading-logarithm parton-shower Monte Carlo models and
next-to-leading- order (NLO) QCD generally underestimate the cross sections for the transverse energies of prompt photons below 7 GeV, while the kT-factorisation QCD calculation agrees with the data better. When the minimum transverse energy of prompt photons is increased to 7 GeV, both NLO QCD and the kT-factorisation calculations are in good agreement with the data.
|
Strong Interactions |
|
halina@mail.desy.de |
| 46 |
ZEUS Collaboration |
Inclusive-jet and dijet cross sections in deep inelastic scattering at HERA |
Inclusive-jet and dijet differential cross sections have been measured in neutral current deep inelastic ep scattering for
exchanged boson virtualities Q2 > 125 GeV2 with the ZEUS detector at HERA using an integrated luminosity of
82 pb-1. Jets were identified in the Breit frame using the kT cluster algorithm. The cross sections are presented as functions of several kinematic and jet variables. The results are also presented in different regions of Q2. Next-to-leading-order QCD calculations describe the measurements well. Regions of phase space where the theoretical uncertainties are small have been identified. Measurements in these regions have the potential to constrain the gluon density in the proton when used as inputs to global fits of the proton parton distribution functions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 47 |
ZEUS Collaboration |
Measurement of azimuthal asymmetries in neutral current deep inelastic scattering at HERA |
The distribution of the azimuthal angle of charged and neutral hadrons relative
to the lepton plane has been studied for neutral current deep inelastic ep
scattering using an integrated luminosity of 45 pb-1 taken with the ZEUS detector
at HERA. The measurements were made in the hadronic centre-of-mass system.
The analysis exploits the energy-flow method, which allows the measurement to
be made over a larger range of pseudorapidity compared to previous results. The
dependence of the moments of the azimuthal distributions on the pseudorapidity
and minimum transverse energy of the final-state hadrons are presented.
Although the predictions from next-to-leading-order QCD describe the data better
than do the Monte Carlo models incorporating leading-logarithm parton showers,
they still fail to describe the magnitude of the asymmetries. This suggests
that higher-order calculations may be necessary to describe these data. |
Strong Interactions |
|
halina@mail.desy.de |
| 48 |
ZEUS Collaboration |
Photoproduction of Events with Rapidity Gaps between Jets at HERA |
The photoproduction of dijet events, where the two jets with the highest
transverse energy are separated by a large gap in pseudorapidity, have been studied
with the ZEUS detector using an integrated luminosity of 39 pb-1 . Rapidity-
gap events are defined in terms of the energy flow between the jets, such that
the total summed transverse energy in this region is less than some value E_T^{CUT}.
The data show a clear excess over the predictions of standard photoproduction
models. This is interpreted as evidence for a strongly interacting exchange of
a color-singlet object. Monte Carlo models which include such a color-singlet
exchange are able to describe the data.
|
Strong Interactions |
|
halina@mail.desy.de |
| 49 |
ZEUS Collaboration |
Measurement of K^0_s, Lambda, Antilambda Production at HERA |
The production of the neutral strange hadrons K0_S, Lambda and
anti-Lambda has been measured in ep collisions at HERA using the ZEUS detector.
Cross sections, baryon-to-meson
ratios, relative yields of strange and charged light hadrons,
Lambda-antiLambda asymmetry
and polarization have been measured in three kinematic regions: Q2 > 25 GeV2,
5 < Q2 < 25 GeV2 and in photoproduction (Q2 ~ 0), in which the presence
of two hadronic jets, each with at least 5 GeV transverse energy, was required.
The measurements agree in general with Monte Carlo models and are consistent
with measurements made at e+e- colliders, except for an enhancement of baryon
relative to meson production in photoproduction. |
Strong Interactions |
|
halina@mail.desy.de |
| 50 |
ZEUS Collaboration |
Jet-radius dependence of inclusive-jet cross sections in deep inelastic scattering at HERA |
Differential inclusive-jet cross sections have been measured for
different jet radii in neutral current deep inelastic ep scattering
for boson virtualities Q2 >125 GeV2 with the ZEUS detector at
HERA using an integrated luminosity of 81.7 pb-1. Jets were
identified in the Breit frame using the kT cluster algorithm in the
longitudinally inclusive mode for different values of the jet radius
R. Differential cross sections are presented as functions of Q2
and the jet transverse energy, ETjet,B. The dependence on R of the
inclusive-jet cross section has been measured for Q2 > 125 and
500 GeV2 and found to be linear with R in the range
studied. Next-to-leading-order QCD calculations give a good
description of the measurements for 0.5 <= R <= 1. A value of
alphas(Mz) has been extracted from the measurements of the inclusive-jet
cross-section dsigma/dQ2 with R=1 for Q2 > 500 GeV2:
alphas(Mz)=0.1207+-0.0014 (stat.) (-0.0033,+0.0035) (exp.) (-0.0023,+0.0022) (th.).
The variation of alphas with ETjet,B is in good agreement with the
running of alphas as predicted by QCD.
|
Strong Interactions |
|
halina@mail.desy.de |
| 51 |
ZEUS Collaboration |
Study of energy dependence of the mean charged multiplicity at HERA |
The hadronic final state has been investigated in inclusive
neutral current deep inelastic ep scattering with the ZEUS detector
at HERA, using an integrated luminosity of 38.6 pb-1.
The mean charged multiplicity and multiplicity distributions have
been studied for the hadrons belonging to the current region
of the Breit frame, as well as for those belonging to the photon
fragmentation region of the hadronic centre-of-mass (HCM) frame.
The results are compared to leading-logarithm parton-shower Monte Carlo predictions
as well as to results of e+e-, pp and previous DIS measurements.
|
Strong Interactions |
|
halina@mail.desy.de |
| 52 |
ZEUS Collaboration |
Measurements of (anti)deauteron and (anti)proton production in DIS at HERA |
A first observation of (anti)deuterons in deep inelastic ep scattering
(DIS) with the ZEUS detector at HERA is reported. The data sample
consists of DIS events at a centre-of-mass energy of 300-318 GeV, and
corresponds to 120 pb-1 integrated luminosity. The measurements are
performed in the central rapidity region for the transverse-momentum
per nucleon mass between 0.3 and 0.7. The particle rates were
extracted and interpreted in terms of the coalescence model. The
(anti)deuteron production rate is approximately three orders of
magnitude suppressed relative to the (anti)proton yield, which is
consistent with the world measurements.
|
Strong Interactions |
|
halina@mail.desy.de |
| 53 |
ZEUS Collaboration |
A first observation of (anti)deuterons in deep inelastic ep scattering |
Three- and four-jet final states have been measured in photoproduction
at HERA using the ZEUS detector and an integrated luminosity of 121 pb-1.
The three-jet results are presented in a wider phase-space and are based
on over seven times the luminosity of the previous HERA publication.
The four-jet photoproduction cross section has been measured for the
first time and represents the highest order process studied at HERA.
The events have been studied in a low-, 25 < Mnj < 50 GeV, and a
high-mass region, Mnj > 50 GeV, where Mnj is the invariant mass of
the n-jet system. The three-jet cross sections have been compared
to an order alpha_s squared perturbative QCD calculation.
In addition, both the three- and four-jet cross sections have
been compared with leading-logarithmic parton-shower Monte Carlo
models, with and without multi-parton interactions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 54 |
ZEUS Collaboration |
Forward-jet production in deep inelastic ep scattering at HERA |
Inclusive forward jet and dijet accompanied by a forward jet cross
sections in neutral current deep inelastic scattering at low
Bjorken-x have been measured with the ZEUS detector at HERA using an
integrated luminosity of 82 pb-1. The explored
phase-space with jet pseudorapidity up to 4.3 is expected to be
particularly sensitive to the dynamics of QCD parton evolution. The
measurements are compared with fixed order QCD calculations and with
leading-logarithm parton-shower Monte Carlo models. |
Strong Interactions |
|
halina@mail.desy.de |
| 55 |
ZEUS Collaboration |
Bose-Einstein correlations of charges and neutral kaons in deep inelastic scattering at HERA |
Bose-Einstein correlations of charged and neutral kaons have been
measured in deep inelastic scattering at HERA using an integrated
luminosity of 121 pb-1 of ep collisions. The two-particle correlation
function was studied as a function of the four momentum difference of
the kaon-pairs, Q12=sqrt(-(p1-p2)2), assuming a Gaussian shape of the
particle source. The radius of the production volume, r, and the
coherence strength factor, lambda, were obtained for both neutral and
charged kaons.56 |
Strong Interactions |
|
halina@mail.desy.de |
| 56 |
ZEUS Collaboration |
Subjet distributions in inclusive-jet production in deep inelastic scattering at HERA |
Subjet distributions have been measured in neutral current deep inelastic ep
scattering with the ZEUS detector at HERA using an integrated luminosity of
81.7 pb-1 . Jets were identified using the kT cluster algorithm in the
longitudinally invariant inclusive mode in the laboratory frame. Subjets, or jet-like
substructures within jets, were then defined as the number of clusters resolved
in a jet by reapplying the jet algorithm at a smaller resolution scale y_cut.
Measurements of subjet distributions are presented as functions of the ratio between
the subjet transverse energy and that of the jet, the difference between the
subjet pseudorapidity (azimuth) and that of the jet, and alpha^sbj,
the angle, as viewed
from the jet centre, between the highest transverse energy subjet and the beam
line in the pseudorapidity-azimuth plane. The measured normalised cross
sections were used to study the pattern of parton radiation by comparing them with
leading-logarithm parton-shower Monte Carlo models and perturbative QCD
calculations.
|
Strong Interactions |
|
halina@mail.desy.de |
| 57 |
ZEUS Collaboration |
Angular correlations in three-jet production in ep collisions at HERA |
Three-jet production in the deep inelastic ep scattering and
photoproduction regimes has been investigated with the ZEUS detector
at HERA using an integrated luminosity of 127 pb-1. Jets were
identified using the k_T cluster algorithm in the longitudinally
invariant inclusive mode. Measurements of differential cross sections
are presented as functions of jet angular correlations between the
three jets in the final state and the proton-beam direction. These
correlations were investigated to separate the contributions
from different color configurations; in particular, angular
correlations sensitive to the presence of a triple-gluon vertex were
analysed. Fixed-order perturbative QCD calculations assuming the values
of the colour factors C_F, C_A and T_F as derived from a variety
of gauge groups were compared to the measurements to study the
underlying gauge group symmetry.
|
Strong Interactions |
|
halina@mail.desy.de |
| 58 |
ZEUS Collaboration |
Multijet production at low x_bj in deep inelastic scattering at HERA |
Inclusive dijet and trijet production in deep inelastic ep scattering
has been measured for 10
| Strong Interactions |
|
halina@mail.desy.de |
|
| 59 |
ZEUS Collaboration |
duplicate of previous |
|
Strong Interactions |
|
|
| 60 |
ZEUS Collaboration |
High-E_T dijet photoproduction at HERA |
The cross section for high-E_T dijet production in photoproduction has
been measured with the ZEUS detector at HERA using an integrated
luminosity of 82 pb-1. The events were required to have a virtuality of
the incoming photon, Q2, of less than 1 GeV2 and a photon-proton
centre-of-mass energy in the range 142 < W_{\gamma p} < 293 GeV. Events
were selected if at least two jets satisfied the transverse-energy
requirements of E_T^{jet1} > 20 GeV and E_T^{jet2} > 15 GeV and
pseudorapidity requirements of -1 < eta^{jet1,2} < 3, with at least one of
the jets satisfying -1 < eta^{jet} < 2.5. These data can be used to
further constrain the parton densities in the proton. The measurements are
compared to next-to-leading-order QCD predictions and show sensitivity to
the choice of the parton densities in the photon and to the effects of
higher orders.
|
Strong Interactions |
|
halina@mail.desy.de |
| 61 |
ZEUS Collaboration |
Scaled momentum spectra in the current region of the Breit frame at HERA |
Charged particle production has been studied in
deep inelastic scattering (DIS) using an integrated luminosity of
about 0.5 fb-1 taken with the ZEUS detector at HERA.
The evolution of scaled momentum distributions as a function
of Q2 has been investigated in the current fragmentation
region of the Breit frame. The fragmentation properties
of the struck quark in DIS are compared to next-to-leading
order calculations with the fragmentation functions
obtained from e+e- experiments. Scaling violations are observed.
The scaled momentum spectra are compared
to modified leading-logarithmic QCD approximation and
to Monte Carlo event generators. In addition,
the limiting spectrum was investigated and compared to the
results from e+e- experiments.
|
Strong Interactions |
|
halina@mail.desy.de |
| 62 |
ZEUS Collaboration |
Dijet photoproduction in association with a leading neutron at HERA |
The cross section for dijet photoproduction in association with a
leading neutron, e+ p -> e+ n j j X, has been measured with the ZEUS
detector, using an integrated luminosity of 45.4 pb-1. Leading neutron
energy and momentum spectra were measured for neutron energy E_n > 180
GeV, and neutron production angle theta_n < 0.75 mrad. The fraction
of dijet events with a leading neutron in the final state was studied
as a function of the jet kinematic variables. Predictions from a
one-pion-exchange model are compared to the data.
|
Strong Interactions |
|
halina@mail.desy.de |
| 63 |
ZEUS Collaboration |
Inclusive diffraction with a large rapidity gap |
The ZEUS detector has been used to study the dissociation of virtual
photons, gamma* p -> X p, in ep collisions at HERA in events with a
large rapidity gap (LRG) between X and the outgoing proton, as well as
in events with a measured leading proton. The data cover photon
virtualities Q2 > 2 GeV2 and masses of the hadronic final state MX > 2
GeV. LRG events were required to have xIP < 0.02, where xIP indicates
the fractional momentum loss of the scattered proton. Events with a
leading proton, detected in the ZEUS leading proton spectrometer, were
required to have the proton carrying at least 90% of the incoming
proton energy. The data are presented in terms of the diffractive
structure function F2D.
|
Strong Interactions |
|
halina@mail.desy.de |
| 64 |
ZEUS Collaboration |
Inclusive diffraction in deep inelastic scattering with the MX method at |
Deep inelastic scattering and its diffractive component, e p -> e X p,
have been studied with the ZEUS detector, covering a wide range in the
photon virtuality (20 < Q2 < 450 GeV2), in the mass of the hadronic
final state X (0.28 < MX < 35 GeV) and in the gamma* p center of mass
energy (37 < W < 245 GeV). The MX distribution of the diffractive
component is statistically extracted from the inclusive MX
distribution, utilizing the difference in the shape of the MX
distribution of diffractive and nondiffractive events. The data are
presented in terms of the diffractive cross section, dsigma/dMX, and
of the diffractive structure function, F2D. The ratio of the
diffractive to the total cross section is also measured.
|
Strong Interactions |
|
halina@mail.desy.de |
| 65 |
ZEUS Collaboration |
Diffractive dijets in photoproduction at HERA |
The ZEUS detector has been used to study the process e p -> e p j j X, in
which the final state contains at least two jets separated from the final
state proton by a large rapidity gap. The data cover photon virtualities
Q^2 < 1 GeV^2. The two jets with highest transverse energy were required to
have E_Tjet1(2) >7.5(6.5) GeV, measured in the laboratory frame.
Differential
cross sections are compared to next-to-leading-order QCD predictions using
different parametrizations of the diffractive parton densities.
|
Strong Interactions |
|
halina@mail.desy.de |
| 66 |
ZEUS Collaboration |
Diffractive dijets in deep inelastic scattering at HERA |
The ZEUS detector has been used to study the process e p -> e p j j X, in
which the final state contains at least two jets separated from the final
state proton by a large rapidity gap. The data cover photon virtualities
5 < Q2 < 100 GeV2. The two jets with highest transverse energy were required
to have E_Tjet1(2) >5(4) GeV, measured in the gamma*p rest frame.
Differential
cross sections are compared to next-to-leading-order QCD predictions using
different parametrizations of the diffractive parton densities.
|
Strong Interactions |
|
halina@mail.desy.de |
| 67 |
ZEUS Collaboration |
Photoproduction of J/Psi with large-t at HERA |
The proton-dissociative diffractive photoproduction of J/Psi mesons
has been studied in ep collisions with the ZEUS detector at HERA using
an integrated luminosity of 112 inverse pb. The cross section has been
measured as a function of the centre-of-mass energy of the
photon-proton system and of the squared four-momentum transfer at the
proton vertex. The results are compared to perturbative QCD
calculations based on BFKL and DGLAP dynamics.
|
Strong Interactions |
|
halina@mail.desy.de |
| 68 |
ZEUS Collaboration |
Deeply Virtual Compton Scattering (DVCS) at HERA |
We present results on the deeply virtual Compton scattering process
gamma* p --> gamma p in ep collisions at sqrt{s} = 318 GeV. The
measurement is based on data taken from the HERA-I running period,
where the ZEUS Leading Proton Spectrometer (LPS) has been used to
measure the momentum of the scattered proton. The cross sections are
measured as a function of the photon virtuality, Q2, the invariant
mass of the gamma p system, W, and differentially in t, the squared
four-momentum transfered at the proton vertex.
|
Strong Interactions |
|
halina@mail.desy.de |
| 69 |
ZEUS Collaboration |
Exclusive dipion electroproduction at HERA |
Measurements of exclusive dipion production using an integrated
luminosity of 195 pb-1, collected with the ZEUS detector at HERA
during 2004-2006, are presented. Events with photon virtuality
satisfying Q2 > 5 GeV2, and the photon-proton centre-of-mass energy 40
< W < 120 GeV were used in the analysis, with the invariant mass of
the dipion system from 1.2 GeV to 5 GeV. The differential cross
sections as functions of the kinematic variables W, Q2, |t| (the four
momentum transfer squared between the dipion system and the virtual
photon) and the angular distributions of the dipion system are
presented.
|
Strong Interactions |
|
halina@mail.desy.de |
| 70 |
ZEUS Collaboration |
Exclusive rho0 electroproduction at HERA |
Exclusive rho0 electroproduction at HERA has been studied with the ZEUS
detector, using 120 pb-1 integrated luminosity collected during
1996-2000. The analysis was carried out in the kinematic range of
photon virtuality of 2 < Q2 < 160 GeV2, and gamma* p center-of-mass
energy of 32 < W < 180 GeV. The results include the Q2 and
W dependence of the gamma* p --> rho0 p cross section and the
distribution of the squared-four-momentum transfer to the proton. The
helicity analysis of the decay-matrix elements of the rho was used to
extract the ratio of longitudinal to transverse gamma* p cross
section as a function of Q2 and W. Finally, the Pomeron trajectory
was extracted. The results were compared to various theoretical
predictions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 71 |
ZEUS Collaboration |
Photoproduction of Upsilon at HERA |
The photoproduction reaction gamma p --> mu+mu- p has been studied in
ep interaction using the ZEUS detector at HERA. The Upsilon vector
meson has been observed in a data sample corresponding to an
integrated luminosity of 250 pb-1. The gamma p cross section
for Upsilon production is presented as a function of W in the range 60
< W < 220 GeV.
|
Strong Interactions |
|
halina@mail.desy.de |
| 72 |
ZEUS Collaboration |
Exclusive dijet production in diffractive deep inelastic scattering |
The data collected in 1998-2000 by the ZEUS detector at the HERA ep
collider have been used to search for exclusive dijet production in
diffractive deep inelastic scattering. The events were selected by
requiring the presence of a large rapidity gap between the direction
of the scattered proton, not observed in the detector, and the
remaining hadronic final state. The jets were reconstructed in the
center of mass system of the diffractive hadronic state with the
k_T-algorithm in the exclusive mode. The properties of events with
only two jets present in the final state were studied in the
region of photon virtuality Q2>20 GeV2, center of mass energy of the
photon-proton system 1600.5.
|
Strong Interactions |
|
halina@mail.desy.de |
| 73 |
ZEUS Collaboration |
Measurement of Prompt Photons with Associated Jets in Photoproduction at HERA |
The photoproduction of prompt photons, together with an accompanying jet, has
been studied in ep collisions at a centre-of-mass energy of 318 GeV with the
ZEUS detector at HERA using an integrated luminosity of 77 pb-1. Cross
sections were measured for the transverse energy of the photon and the
jet larger than 5 and 6 GeV, respectively. The differential gamma+jet
cross sections were reconstructed as functions of the transverse
energy, pseudorapidity and x(gamma)^obs, the fraction of the incoming
photon momentum taken by the photon-jet system. Predictions based on
leading-logarithm parton-shower Monte Carlo models and
next-to-leading- order (NLO) QCD generally underestimate the cross
sections for the transverse energies of prompt photons below 7 GeV,
while the kT-factorisation QCD calculation agrees with the data
better. When the minimum transverse energy of prompt photons is
increased to 7 GeV, both NLO QCD and the kT-factorisation calculations
are in good agreement with the data.
|
Strong Interactions |
|
halina@mail.desy.de |
| 74 |
ZEUS Collaboration |
Multi-jet cross sections in charged current deep inelastic scattering with HERA II |
Differential jet cross sections have been measured in charged current
deep inelastic ep scattering at high boson virtualities Q^2
with the ZEUS detector at HERAII using an integrated luminosity of ~200
pb-1. Jets were identified using the k_T cluster algorithm in the
longitudinally invariant inclusive mode. Cross sections are presented
for inclusive-jet production as functions of Q^2, x_Bj and the jet
transverse energy and pseudorapidity. The dijet invariant mass cross
section is also presented. Observation of three jet events in
charged-current processes is reported for the first
time. Leading-logarithm parton-shower Monte Carlo model and
next-to-leading-order QCD calculations are compared to the
measurements.
|
Strong Interactions |
|
halina@mail.desy.de |
| 75 |
ZEUS Collaboration |
Dijets cross sections in DIS with HERA II |
Dijet differential cross sections have been measured in neutral current
deep inelastic ep scattering for exchanged boson virtualities 125 < Q2 <
5000 GeV2 with the ZEUS detector at HERA using an integrated luminosity of
209 pb-1. Jets were identified in the Breit frame using the k_T cluster
algorithm. Jet cross sections are presented as functions of several
kinematic and jet variables. The results are also presented in different
regions of Q2. Next-to-leading-order QCD calculations describe the
measurements well.
|
Strong Interactions |
|
halina@mail.desy.de |
| 76 |
ZEUS Collaboration |
Inclusive-jet production in neutral-current deep inelastic ep scattering at high Q**2 with HERA II |
Inclusive-jet production in neutral-current deep inelastic ep
scattering at high Q**2 has been investigated with the ZEUS
detector using all the available luminosity from the HERA II
running period. Jets were identified in the Breit frame using
the k_T cluster algorithm in the longitudinally invariant
inclusive mode. Measurements of differential cross sections
are presented as functions of Q**2 and the jet transverse
energy, E^jet_T,B. Regions of phase space have been identified
where the theoretical uncertainties are small. Measurements in
these regions have the potential to constrain the gluon
density in the proton. Next-to-leading order QCD calculations are
compared to the results and used to make a determination of
the strong coupling constant, alpha_s(M_Z). Furthermore, the
energy-scale dependence of alpha_s has been determined from the
measured differential cross section as a function of E^jet_T,B
and compared to the running of alpha_s as predicted by QCD.
|
Strong Interactions |
|
halina@mail.desy.de |
| 77 |
ZEUS Collaboration |
Jet substructure in neutral-current deep inelastic ep scattering at high Q**2 with HERA II |
Jet substructure for jets produced in the deep inelastic ep scattering
regime has been studied for exchanged boson virtualities Q2>125 GeV**2
with the ZEUS detector at HERA using all the available luminosity from
the HERA II running period. Jets were identified in the laboratory frame
using the kT cluster algorithm in the longitudinally inclusive mode. The
substructure of jets has been investigated in terms of the jet shape and
subjet multiplicity in different regions of the jet transverse energy and
pseudorapidity. Next-to-leading-order QCD calculations are compared to the
measurements. A value of alpha_s(M_Z) is extracted from the measurements.
|
Strong Interactions |
|
halina@mail.desy.de |
| 78 |
ZEUS Collaboration |
Measurement of the neutral-current deep-inelastic scattering cross |
The ZEUS experiment at the ep collider HERA has performed a new
measurement of the deep-inelastic scattering cross-sections with the data
collected during the years 2006 and 2007. The measurement is optimized for
the kinematic region of large values of the inelasticity y where several
experimental challenges need to be overcome. The results were compared to
the expectations of the Standard Model obtained with several parton
density functions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 79 |
ZEUS Collaboration |
W Production and the Search for Events with an Isolated High-Energy Lepton and Missing Transverse Momentum at HERA |
A search for events with isolated high transverse energy leptons and large missing transverse momentum has been performed with the ZEUS detector at HERA using data samples taken during the 1996-2007 running period. The results are compared to the Standard Model predictions. The cross section for single production of W bosons at HERA is estimated.
|
Physics Beyond the Standard Model |
|
halina@mail.desy.de |
| 80 |
ZEUS Collaboration |
Measurement of high-Q2 neutral current deep inelastic e- p scattering cross sections with longitudinally polarised electrons at ZEUS |
Measurements of the neutral current cross sections for deep inelastic scattering in e-p collisions at HERA with longitudinally polarised electron beams are presented. Single differential cross sections in Q2, x and y, and double differential cross sections in Q2 and x are shown in the kinematic region of Q2 > 185 GeV2 separately for positively and negatively polarised electrons. The measurements are based on an integrated luminosity of 177 pb-1 collected by the ZEUS detector from 2004 to 2006 with a centre-of-mass energy of 318 GeV. The structure function xF3 is measured by combining the e-p data presented in this paper with previously measured unpolarised e+p neutral current data. The asymmetry parameter A- is used to demonstrate the parity violating effects of electroweak interactions. The Standard Model agrees well with all measurements.
|
Strong Interactions |
Submitted also to High-Energy Electroweak Physics |
halina@mail.desy.de |
| 81 |
ZEUS Collaboration |
Measurement of high-Q2 neutral current deep inelastic e- p scattering cross sections with longitudinally polarised electrons at ZEUS |
Measurements of the neutral current cross sections for deep inelastic scattering in e-p collisions at HERA with longitudinally polarised electron beams are presented. Single differential cross sections in Q2, x and y, and double differential cross sections in Q2 and x are shown in the kinematic region of Q2 > 185 GeV2 separately for positively and negatively polarised electrons. The measurements are based on an integrated luminosity of 177 pb-1 collected by the ZEUS detector from 2004 to 2006 with a centre-of-mass energy of 318 GeV. The structure function xF3 is measured by combining the e-p data presented in this paper with previously measured unpolarised e+p neutral current data. The asymmetry parameter A- is used to demonstrate the parity violating effects of electroweak interactions. The Standard Model agrees well with all measurements.
|
High-Energy Electroweak Physics |
Submitted also to Strong Interactions |
halina@mail.desy.de |
| 82 |
ZEUS Collaboration |
Measurement of high-Q2 charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA |
Measurements of the cross sections for charged current deep inelastic scattering in e-p collisions with a longitudinally polarised electron beam are presented. The measurements are based on a data sample with an integrated luminosity of 174 pb-1 collected with the ZEUS detector at HERA from 2004 to 2006 at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the electron beam. A fit to these measurements yields an upper limit on the right-handed charged cross section and a lower limit on the mass of a right-handed W boson. The differential cross sections dσ/dQ2, dσ/dx and dσ/dy for Q2>200 GeV2 are presented. In addition d2σ/dxdQ2 has been measured in the kinematic range 280 GeV2 < Q2 < 30000 GeV2 and 0.015 < x < 0.65. The measured cross sections are compared with the predictions of the Standard Model. An electroweak analysis of the measurements yields a value for the mass of the W boson.
|
Strong Interactions |
Submitted also to High-Energy Electroweak Physics |
halina@mail.desy.de |
| 83 |
ZEUS Collaboration |
Measurement of high-Q2 charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA |
Measurements of the cross sections for charged current deep inelastic scattering in e-p collisions with a longitudinally polarised electron beam are presented. The measurements are based on a data sample with an integrated luminosity of 174 pb-1 collected with the ZEUS detector at HERA from 2004 to 2006 at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the electron beam. A fit to these measurements yields an upper limit on the right-handed charged cross section and a lower limit on the mass of a right-handed W boson. The differential cross sections dσ/dQ2, dσ/dx and dσ/dy for Q2>200 GeV2 are presented. In addition d2σ/dxdQ2 has been measured in the kinematic range 280 GeV2 < Q2 < 30000 GeV2 and 0.015 < x < 0.65. The measured cross sections are compared with the predictions of the Standard Model. An electroweak analysis of the measurements yields a value for the mass of the W boson.
|
High-Energy Electroweak Physics |
Submitted also to Strong Interactions |
halina@mail.desy.de |
| 84 |
ZEUS Collaboration |
Combined Electroweak and QCD analysis of ZEUS data, including DIS cross sections with polarised lepton beams |
A NLO QCD analysis on ZEUS jet-production data and inclusive cross-section data, including data with polarised lepton beams, is presented. The analysis is used to extract the parton distribution functions of the proton and is extended to fit electroweak parameters.
|
Strong Interactions |
|
halina@mail.desy.de |
| 85 |
ZEUS Collaboration |
Measurement of High-Q2 Deep Inelastic Scattering Cross Sections with a Longitudinally Polarised Positron Beam at HERA |
The cross sections for charged- and neutral-current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an integrated luminosity of 140 pb-1 at sqrt{s}=318 GeV, are given for both positive and negative values of the longitudinal polarisation of the positron beam. Single differential cross sections are presented for the kinematic region Q2>200 GeV2. The measured cross sections are compared to the predictions of the Standard Model.
|
Strong Interactions |
Submitted also to High-Energy Electroweak Physics |
halina@mail.desy.de |
| 86 |
ZEUS Collaboration |
Measurement of High-Q2 Deep Inelastic Scattering Cross Sections with a Longitudinally Polarised Positron Beam at HERA |
The cross sections for charged- and neutral-current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an integrated luminosity of 140 pb-1 at sqrt{s}=318 GeV, are given for both positive and negative values of the longitudinal polarisation of the positron beam. Single differential cross sections are presented for the kinematic region Q2>200 GeV2. The measured cross sections are compared to the predictions of the Standard Model.
|
High-Energy Electroweak Physics |
Submitted also to Strong Interactions |
halina@mail.desy.de |
| 87 |
ZEUS Collaboration |
Measurement of Multi-lepton Production with the ZEUS detector at HERA |
Multi-lepton production is studied in positron-proton and electron-proton collision data. Multi-electron and multi-muon event topologies are studied. The data was collected during 1996-2007 using the ZEUS detector at HERA. The results are compared with the Standard Model prediction. Deviations from the Standard Model at high dilepton invariant mass are searched for.
|
High-Energy Electroweak Physics |
Submitted also to Physics Beyond the Standard Model |
halina@mail.desy.de |
| 88 |
ZEUS Collaboration |
Measurement of Multi-lepton Production with the ZEUS detector at HERA |
Multi-lepton production is studied in positron-proton and electron-proton collision data. Multi-electron and multi-muon event topologies are studied. The data was collected during 1996-2007 using the ZEUS detector at HERA. The results are compared with the Standard Model prediction. Deviations from the Standard Model at high dilepton invariant mass are searched for.
|
Physics Beyond the Standard Model |
Submitted also to High-Energy Electroweak Physics |
halina@mail.desy.de |
| 89 |
ZEUS Collaboration |
Search for contact interactions with the ZEUS detector in HERA data |
A search for physics beyond the Standard Model is performed with high-Q2 neutral current deep inelastic scattering events. New data on scattering of longitudinally polarized electrons and positrons from HERA II running are combined with electron and positron data from HERA I. No significant deviations from the Standard Model predictions are observed. Limits are derived on the effective mass scale in eeqq contact interactions, on the mass to the Yukawa coupling ratio for heavy-leptoquark models, on the effective Planck-mass scale in models with large extra dimensions and on the quark charge radius.
|
Physics Beyond the Standard Model |
|
halina@mail.desy.de |
| 90 |
KLOE Collaboration |
KLOE measurement of the scalar Form-Factor slope for K_L -> pi mu nu |
Semileptonic kaon decays offer possibly the cleanest way to obtain an accurate value of the Cabibbo angle, or better, Vus. At present,
the largest uncertainty in calculating Vus from the decay rate, is due to the difficulties in computing the matrix element of the K -> pi transition.
The matrix element of K_L -> pi mu nu decay is expressed in terms of kaon and pion four-momenta, P and p respectively, and using form factors f+(t) and f0(t), where t=(P-p)2.
It is customary to expand the scalar form factor f0(t) in powers of t as f0(t)=f+(0)[1+lambda0 t/m2+..], where m is the mass of the charged pion, and only the linear term is retained. The form factor at zero momentum transfer,
f+(0), is valuated from theory, while the form factor slope, lambda0, has to be
determined experimentally from K_L -> pi mu nu decay spectra.
The best sensitivity to lambda0 is achieved in KLOE by using the neutrino
energy spectrum. Such a measurement is possible because of the tagging technique,
consisting of identifying K_L decays through the selection of K_S -> pi+pi-
decay near the e+e- interaction point. This strategy allows to measure KL momentum
with good precision. We present the results of this analysis, based on 330 pb^-1 of data acquired during years 2001 and 2002.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 91 |
KLOE Collaboration |
KLOE measurement of BR(K_L -> pi e nu gamma) |
The study of radiative K_L decays offers the possibility to obtain
informations on kaon structure and to test predictions of the Chiral
Perturbation Theory. Two different processes contribute to photon
emission in K_L -> pi e nu gamma decay (KLe3g in the following): the inner
bremsstrahlung (IB) and the direct emission (DE). The latter is due to photon radiation from
intermediate hadronic states.
To compare with theoretical predictions and present best experimental
results, we measured the ratio R = BR(KLe3g; E*>30 MeV, theta*>20deg)/BR(KLe3), where
E* and theta* are the photon energy and the angle between electron and photon in
K_L rest frame, respectively. With these cuts the theoretical predictions for R
range between 0.95% and 0.99% . The DE contribution is expected to
be less than 1% of the IB one.
KLOE measurement benefits of the tagging technique, which consists of
identifying K_L decays through the selection of K_S -> pi+pi- decay near the
e+e- interaction point. This strategy allows to achieve an optimal background
rejection, and also to measure K_L momentum with good precision.
We present the results of this analysis, based on 330 pb^-1 of data acquired
during years 2001 and 2002.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 92 |
KLOE Collaboration |
Direct search of K_S -> e+e- decay with the KLOE detector |
K_S -> e+e- decay is a DeltaS = 1 weak neutral current process. The Standard
Model expectation for its BR is 1.6*10^-15, which has been evaluated
by Chiral Perturbation Theory with 10% error. The best experimental limit on
this decay, achieved by CPLEAR experiment, is BR<1.4*10^-7 at 90% CL.
We performed a direct search of K_S -> e+e- decay by analysing 1.3 fb^-1 of
data. The analysis exploits the excellent
KLOE drift chamber momentum resolution to identify the signal through e+e-
invariant mass reconstruction. Further background rejection comes from
calorimeter particle identification, which is based on time of flight, shower
longitudinal profile and E/p.
The result of this search is presented, which improves on the previous
experimental limit by a factor of 10.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 93 |
KLOE Collaboration |
KLOE measurement of BR(K_S -> gamma gamma) |
A precise measurement of the K_S -> gamma gamma rate is an important test of
Chiral Perturbation Theory predictions. The decay amplitude can be evaluated
at the leading p4 order providing an estimate of the BR for this decay
of (2.1+-0.1)*10^-6. The latest experimental determination of
BR(K_S -> gamma gamma) is a precise measurement from NA48,
(2.78+-0.07)*10^-6, which differs from ChiPT p4 prediction of about
30%. This seems to indicate the presence of important contributions from higher
order corrections.
KLOE analysis on 1.6 fb^-1 of data acquired during years 2001-2002 and
2004-2005 benefits from the tagging technique, which allows for the first time
this decay to be identified with a pure K_S ``beam'', without the
background from K_L -> gamma gamma decay, and with completely different
systematics respect to fixed target experiments.
Event counting is performed from a fit to the bidimensional distribution of the
two-photon invariant mass versus the angle between photon momenta in the K_S rest frame.
In this plane the best separation is achieved between the signal and the main source
of background, which is represented by K_S -> pi0pi0 events with two missing
photons. The result of this analysis is presented, which is competitive with present
measurements. |
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 94 |
Antoni Szczurek and Sergey Baranov |
"Inclusive $J/\psi$ production
in pp collisions at RHIC" |
Inclusive cross sections for $J/\psi$ production
in proton-proton collisions were calculated in the $k_t$-factorization
approach for the RHIC energy. Different unintegrated gluon distributions
from the literature were used. Several mechanisms were considered,
including direct color-singlet mechanism, radiative decays of $\chi_c$
mesons, decays of $\psi'$, open-charm associated production of $J/\psi$
as well as weak decays of B mesons.
Surprisingly, we have found that radiative $\chi_c$ decays constitute
the dominant mechanism of $J/\psi$ production. This process cannot
be consistently treated within collinear-factorization approach.
Our results were compared with recent RHIC data.
The new precise data at small transverse momenta impose stringent
constraints on UGDFs. Many UGDFs from the literature are inconsistent
with the new data.
The Kwieci\'nski UGDFs give the best description of the data.
In order to verify the mechanism suggested
here we propose $J/\psi$ -- jet correlation measurement and
an independent measurement of $\chi_c$ meson production
in $\pi^+ \pi^-$ and/or $K^+ K^-$ decay channels.
|
Strong Interactions |
Quite new view of J/psi production will be shown |
antoni.szczurek@ifj.edu.pl |
| 95 |
Antoni Szczurek |
Exclusive production of scalar, pseudoscalar and vector quarkonia
in pp and ppbar collisions at high energies |
We discuss double-diffractive double-elastic production of the
$\eta'$-meson in the $pp \to p\eta'p$ reaction within the
formalism of unintegrated gluon distribution functions (UGDF). We
estimate also the contribution of $\gamma^* \gamma^* \to \eta'$ fusion.
The distributions in the Feynman $x_F$ (or rapidity), transferred
four-momentum squared between initial and final protons ($t_1$, $t_2$)
and azimuthal angle difference between outgoing protons ($\Phi$)
are calculated.
The deviations from the $\sin^2(\Phi)$ dependence predicted by
one-step vector-vector-pseudoscalar coupling are quantified and discussed.
The results are compared with the results of the WA102
collaboration at CERN.
Most of the models of UGDF from the literature
give too small cross section as compared to the WA102 data
and predict angular distribution in relative azimuthal angle strongly
asymmetric with respect to $\pi/2$. This points at a different mechanism
at the WA102 energy.
Predictions for RHIC, Tevatron and LHC are given.
We find that the normalization, $t_{1,2}$
dependence as well as deviations from $\sin^2(\Phi)$ of
double-diffractive double-elastic cross section are extremely sensitive
to the choice of UGDF. Possible implications for UGDFs are discussed.
We calculate several differential distributions for exclusive scalar
heavy quarkonia ($\chi_c(0^{++})$ and $\chi_b(0^{++}$)) production
in proton-antiproton collisions at the Tevatron energy
in terms of UGDFs.
The $g^* g^* \to \chi_Q$ transition form factors are calculated
as a function of gluon virtualities.
Different models of UGDFs are used.
We discuss correlations in azimuthal angle between outgoing proton
and antiproton.
Distortions from $cos^2(\Phi)$ are obtained and discussed.
The role of the second form factor is quantified.
Approximations used in the literature are discussed in detail.
We calculate several differential distributions in $t_1, t_2, x_F, \phi$
for exclusive $J/\Psi$ production in proton-proton (RHIC, LHC) and
proton-antiproton (FAIR, Tevatron) collisions. The photon-pomeron and
pomeron-photon exchanges are included in a vector-dominance -- soft
pomeron exchange model and in a QCD-inspired model
based on the formalism of unintegrated gluon distributions (UGDF).
Different models of UGDFs are used.
We discuss correlations in azimuthal angle between outgoing proton
and antiproton and in the ($t_1, t_2$) space.
The cross section of the photon-pomeron and pomeron-photon exchange
dominate at $y \ll$ 0 and $y \gg$ 0, respectively.
This opens a possibility to study exclusive photoproduction of
heavy vector mesons at energies much larger than possible at the HERA
accelerator. Large interference terms are found in the broad range
of rapidities and transverse momenta.
The reaction discussed here constitutes dominant nonreduceable
background in recently proposed searches for odderon exchange.
|
Strong Interactions |
"This is based on results obtained recently in collaboration with R.Pasechnik, O.Teryaev and W. Schaefer" |
antoni.szczurek@ifj.edu.pl |
| 96 |
ZEUS Collaboration |
Measurement of D* Meson Production in DIS ep Scattering at Low Q2 |
The production of D*(2010) mesons in ep scattering in the range of
exchanged photon virtuality 0.05 < Q^2 < 0.7 GeV^2 has been measured
with the ZEUS detector at HERA using an integrated luminosity of 82
pb^-1. The decay channels D*+ -> D0 pi+ with D0 -> K- pi+ and
corresponding antiparticle decay were used to identify D* mesons and
the ZEUS beampipe calorimeter was used to identify the scattered
electron. Differential D* cross-sections as functions of Q^2,
inelasticity, y, transverse momentum of the D* meson, p_T(D*), and
pseudorapidity of the D* meson, eta(D*) have been measured in the
kinematic region, 0.02
| Strong Interactions |
|
halina@mail.desy.de |
|
| 97 |
ZEUS Collaboration |
Measurements of Charm Production Cross Sections and Fragmentation Fractions in DIS |
Charm production in deep inelastic scattering has been measured with the
ZEUS detector at HERA using an integrated luminosity of 82 pb-1.
Charm has been tagged by reconstructing D*+, D0, D+ and Ds+ (+ c.c.)
charm mesons. The charm hadrons were measured in the kinematic
range pT(D*+,D0,D+) > 3 GeV, pT(Ds+)>2 GeV and |eta(D)| < 1.6
for 1.5 < Q^2 < 1000 GeV^2 and 0.02 < y < 0.7. The production cross
sections were used to extract charm fragmentation ratios and the fraction
of c quarks hadronising into a particular charm meson in the kinematic
range considered. The cross sections were compared to the predictions of
next-to-leading-order QCD, and extrapolated to the full kinematic region
in pT(D) and eta(D) in order to determine the open-charm contribution,
F2ccbar(x,Q^2), to the proton structure function F2.
|
Strong Interactions |
Also submitted to Flavor Physics and CP Violation |
halina@mail.desy.de |
| 98 |
ZEUS Collaboration |
Measurements of Charm Production Cross Sections and Fragmentation Fractions in DIS |
Charm production in deep inelastic scattering has been measured with the
ZEUS detector at HERA using an integrated luminosity of 82 pb-1.
Charm has been tagged by reconstructing D*+, D0, D+ and Ds+ (+ c.c.)
charm mesons. The charm hadrons were measured in the kinematic
range pT(D*+,D0,D+) > 3 GeV, pT(Ds+)>2 GeV and |eta(D)| < 1.6
for 1.5 < Q^2 < 1000 GeV^2 and 0.02 < y < 0.7. The production cross
sections were used to extract charm fragmentation ratios and the fraction
of c quarks hadronising into a particular charm meson in the kinematic
range considered. The cross sections were compared to the predictions of
next-to-leading-order QCD, and extrapolated to the full kinematic region
in pT(D) and eta(D) in order to determine the open-charm contribution,
F2ccbar(x,Q^2), to the proton structure function F2.
|
Flavour Physics and CP Violation |
Also submitted to Strong Interactions |
halina@mail.desy.de |
| 99 |
ZEUS Collaboration |
Diffractive Photoproduction of D*+/-(2010) at HERA |
Diffractive photoproduction of D*+/-(2010) mesons was measured with the
ZEUS detector at the ep collider HERA, using an integrated luminosity
of 78.6 pb-1. The D* mesons were reconstructed in the kinematic range:
transverse momentum p_T(D*) > 1.9 GeV and pseudorapidity
-1.6 < eta(D*) < 1.6, using the decay D*+ -> D0 pi+_s followed by
D0 -> K- pi+ (+c.c.). Diffractive events were identified by a large gap
in pseudorapidity between the produced hadronic state and the outgoing
proton. Cross sections are reported for photon-proton centre-of-mass
energies in the range 130 < W < 300 GeV and for photon virtualities
Q^2 < 1 GeV^2, in two ranges of the Pomeron fractional momentum
x_pom < 0.035 and x_pom < 0.01. The relative contribution of diffractive
events to the inclusive D*+/-(2010) photoproduction cross section is
about 6%. The data are in agreement with perturbative QCD calculations
based on various parameterisations of diffractive parton distribution
functions. The results are consistent with diffractive QCD factorisation.
|
Strong Interactions |
|
halina@mail.desy.de |
| 100 |
ZEUS Collaboration |
Measurement of open beauty production at HERA in the D* muon final state |
The production of beauty quarks with a D* and a muon in the final state
has been measured with the ZEUS detector at HERA using an integrated
luminosity of 114 pb-1. Low transverse momentum thresholds for the muon
and D* meson allow a measurement of beauty production closer to the
production threshold than previous measurements. The beauty signal was
extracted using the charge correlations and angular distributions of the
muon with respect to the D* meson. Cross sections for photoproduction and
deep inelastic scattering are somewhat higher than, but compatible with,
next-to-leading-order QCD predictions, and compatible with other
measurements.
|
Strong Interactions |
May be of interest also to Flavour Physics and CP Violation |
halina@mail.desy.de |
| 101 |
ZEUS Collaboration |
Measurement of excited charm and charm-strange mesons production at HERA |
The production of excited charm, D_1(2420)^0 and D_2^*(2460)^0,
and charm-strange, D_s1(2536)+/-, mesons has been measured with
the ZEUS detector at HERA using an integrated luminosity of 126 pb^-1.
The mesons have been reconstructed in the D^*+ pi^-, D^+ pi^-, D^*+ K^0_s
and D^0 K^+ (+c.c.) final states. The measured yields have been converted
to the rates of c quarks hadronising as a given excited D meson and to
the ratios of the dominant D_2^*(2460)^0 and D_s1(2536)+/- branching ratios.
A search for the radially excited charm meson, D^*(2640)+/-, in the
D^*+ pi^+ pi^- (+c.c.) final state has been also performed.
The results are compared with those measured previously and with theoretical
expectations.
|
Flavour Physics and CP Violation |
|
halina@mail.desy.de |
| 102 |
ZEUS Collaboration |
Measurement of beauty production from dimuon events at HERA |
Beauty production with events in which two muons are observed in the final
state has been measured with the ZEUS detector at HERA using an integrated
luminosity of 114 pb-1. A low pt threshold for muon identification,
in combination with the large rapidity coverage of the ZEUS muon system,
gives access to essentially the full phase space for beauty production.
The total cross section for beauty production in ep collisons at
sqrt(s)=318 GeV has been measured. Differential cross sections and a
measurement of bbbar correlations are also obtained, and compared to
other beauty cross section measurements, MC models, and NLO QCD predictions.
The latter agree with the data within errors, but tend to lie below the
measurements. The shapes of all distributions are well described.
|
Strong Interactions |
May be of interested also to Plavour Physics and CP Violation |
halina@mail.desy.de |
| 103 |
ZEUS Collaboration |
Measurement of the charm fragmentation function in D* photoproduction at HERA |
The charm fragmentation function has been measured in D* photoproduction with
the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The
fragmentation function is measured versus z, the ratio of E+p_parallel for the
D* meson and that for the associated jet, where E is the energy and p_parallel
the longitudinal momentum relative to the jet axis. Jets were reconstructed
using the k_T clustering algorithm and required to have transverse energy
greater than 9 GeV. The D* meson associated with the jet was required to have
a transverse momentum greater than 2 GeV. The measured function is compared to
different fragmentation models incorporated in leading-logarithm Monte Carlo
simulations and a next-to-leading-order calculation. The results are similar
to those from e+e- experiments.
|
Strong Interactions |
Also submitted to Flavour Physics and CP Violation |
halina@mail.desy.de |
| 104 |
ZEUS Collaboration |
Measurement of the charm fragmentation function in D* photoproduction at HERA |
The charm fragmentation function has been measured in D* photoproduction with
the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The
fragmentation function is measured versus z, the ratio of E+p_parallel for the
D* meson and that for the associated jet, where E is the energy and p_parallel
the longitudinal momentum relative to the jet axis. Jets were reconstructed
using the k_T clustering algorithm and required to have transverse energy
greater than 9 GeV. The D* meson associated with the jet was required to have
a transverse momentum greater than 2 GeV. The measured function is compared to
different fragmentation models incorporated in leading-logarithm Monte Carlo
simulations and a next-to-leading-order calculation. The results are similar
to those from e+e- experiments.
|
Flavour Physics and CP Violation |
Also submitted to Strong Interactions |
halina@mail.desy.de |
| 105 |
ZEUS Collaboration |
Beauty Production at ZEUS using Semileptonic Decays into Electrons |
Beauty quark production in ep collisions has been studied using the
data collected in 1996-2000 with the ZEUS detector at HERA, which
corresponds to an integrated luminosity of 120 pb-1. Photoproduction
(Q^2 < 1 GeV^2) events with two jets and an electron candidate are
selected in order to study semileptonic decays of beauty quarks into
electrons. For electron identification several discriminating input
variables are combined in a likelihood test function. With this
statistical method both the fractions of beauty and charm in the
sample could be determined. Total and differential cross-sections
have been measured and are compared to QCD predictions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 106 |
ZEUS Collaboration |
Measurement of F_2charm at HERA |
Inclusive production of D*(2010) mesons in deep inelastic scattering has
been measured with the ZEUS detector at HERA II using the data taken during
the 2003-5 running period. Differential D* cross sections are compared
to next-to-leading-order QCD theoretical predictions. The observed
cross section is extrapolated to the full kinematic region in pt(D*)
and eta(D*) in order to determine the open charm contribution,
F_2^{ccbar}, to the proton structure function. The data from HERA I
and HERA II are compared to those from the QCD fit.
|
Strong Interactions |
|
halina@mail.desy.de |
| 107 |
ZEUS Collaboration |
Charm production at HERA using Lifetime tags |
Charm production has been measured with the ZEUS detector at
HERA II using the silicon vertex detector. The vertex detector was
installed during the HERA upgrade to improve the tracking and vertexing.
The resolution of the vertex detector allows charm to be selected by
measuring the secondary vertex from a D-meson decay or from the impact
parameter of identified leptons. Cross sections from the 2003-2005 data
based on lifetime tags are presented and compared to pQCD predictions.
|
Strong Interactions |
|
halina@mail.desy.de |
| 108 |
ZEUS Collaboration |
Measurement of beauty production in deep inelastic scattering at HERA |
Beauty production in deep inelastic scattering with events in which a
muon and a jet are observed in the final state has been measured with
the ZEUS detector including HERA II data. Differential cross sections in
Q^2, p_T(mu), eta(mu), p_T(jet) and eta(jet) are compared to
theoretical predictions.
Double differential cross sections are measured and the open beauty
contribution F_2^{bbbar} to the proton structure function is determined.
|
Strong Interactions |
|
halina@mail.desy.de |
| 109 |
ZEUS Collaboration |
Measurement of beauty production in deep inelastic scattering at HERA |
Beauty production in deep inelastic scattering with events in which a
muon and a jet are observed in the final state has been measured with
the ZEUS detector including HERA II data. Differential cross sections in
Q^2, p_T(mu), eta(mu), p_T(jet) and eta(jet) are compared to
theoretical predictions.
Double differential cross sections are measured and the open beauty
contribution F_2^{bbbar} to the proton structure function is determined.
|
Strong Interactions |
|
halina@mail.desy.de |
| 110 |
ZEUS Collaboration |
Measurement of Beauty Photoproduction in dijet events at HERA |
Beauty photoproduction in dijet events has been measured at HERA with the
ZEUS detector. Beauty was identified in events with a muon in the final
state by using the transverse momentum of the muon relative to the closest
jet. Lifetime information from the silicon vertex detector was also used to
identify the long-lived particles: the impact parameter of the muon
or the displacement of a secondary vertex with respect to the primary
vertex were exploited to discriminate between beauty and background.
Cross sections are measured and compared with QCD predictions and previous
measurements.
|
Strong Interactions |
|
halina@mail.desy.de |
| 111 |
ZEUS Collaboration |
Measurement of inelastic J/psi helicity distributions using |
The decay angular distributions for inelastic photoproduction
of J/psi mesons have been measured in ep collisions with the
ZEUS detector at HERA using an integrated luminosity of ~250 pb-1
collected between 2003 and 2006.
J/psi mesons are identified using the decay mode J/psi \rightarrow
mu^+ mu^- and were measured in the range 50 < W < 180 GeV, where
W is the photon--proton centre--of--mass energy.
The polar and azimuthal distributions of the mu^+ in the J/psi rest
frame are measured as a function of p_T, for p_T > 1 GeV and z > 0.4,
and as function of z, for p_T > 1 GeV and 0.1 < z < 0.9, where p_T
is the transverse momentum of the J/psi in the laboratory frame and
z is the fraction of the incident photon energy carried by the J/psi
in the proton rest frame.
The experimental results are compared to the ZEUS and H1 results
obtained using HERA I data. ZEUS combined HERA I and HERA II measurements
are also shown and compared with theoretical predictions at leading order |
Strong Interactions |
|
halina@mail.desy.de |
| 112 |
Aidan Robson (CDF Collaboration) |
Searches for Higgs->WW at CDF |
We present results from the CDF experiment at the Tevatron of searches for a Standard Model Higgs boson in its decay to two W bosons, where the W bosons each decay to an electron or muon.
These channels provide good sensitivity to a high mass Higgs, such that for Higgs masses of around 160GeV/c2 the expected cross-section exclusion limit in the case of non-observation is close to the Standard Model cross-section prediction.
|
High-Energy Electroweak Physics |
|
a.robson@physics.gla.ac.uk |
| 113 |
ZEUS Collaboration |
Measurement of Prompt Photons with Associated Jets in Photoproduction at HERA |
The photoproduction of prompt photons, together with an accompanying jet, has
been studied in ep collisions at a centre-of-mass energy of 318 GeV with the
ZEUS detector at HERA using an integrated luminosity of 77 pb-1. Cross
sections were measured for the transverse energy of the photon and the
jet larger than 5 and 6 GeV, respectively. The differential gamma+jet
cross sections were reconstructed as functions of the transverse
energy, pseudorapidity and x(gamma)^obs, the fraction of the incoming
photon momentum taken by the photon-jet system. Predictions based on
leading-logarithm parton-shower Monte Carlo models and
next-to-leading- order (NLO) QCD generally underestimate the cross
sections for the transverse energies of prompt photons below 7 GeV,
while the kT-factorisation QCD calculation agrees with the data
better. When the minimum transverse energy of prompt photons is
increased to 7 GeV, both NLO QCD and the kT-factorisation calculations
are in good agreement with the data.
|
Strong Interactions |
Resubmitted as was non-confirmed first time |
halina@mail.desy.de |
| 114 |
ZEUS Collaboration |
Measurements of (anti)deuteron and (anti)proton production in DIS at HERA |
A first observation of (anti)deuterons in deep inelastic ep scattering
(DIS) with the ZEUS detector at HERA is reported. The data sample
consists of DIS events at a centre-of-mass energy of 300-318 GeV, and
corresponds to 120 pb-1 integrated luminosity. The measurements are
performed in the central rapidity region for the transverse-momentum
per nucleon mass between 0.3 and 0.7. The particle rates were
extracted and interpreted in terms of the coalescence model. The
(anti)deuteron production rate is approximately three orders of
magnitude suppressed relative to the (anti)proton yield, which is
consistent with the world measurements. |
Strong Interactions |
Submitted second time with typo corrected in the title |
halina@mail.desy.de |
| 115 |
ZEUS Collaboration |
Multi-jet final states in photoproduction at HERA |
Three- and four-jet final states have been measured in photoproduction
at HERA using the ZEUS detector and an integrated luminosity of 121 pb-1.
The three-jet results are presented in a wider phase-space and are based
on over seven times the luminosity of the previous HERA publication.
The four-jet photoproduction cross section has been measured for the
first time and represents the highest order process studied at HERA.
The events have been studied in a low-, 25 < Mnj < 50 GeV, and a
high-mass region, Mnj > 50 GeV, where Mnj is the invariant mass of
the n-jet system. The three-jet cross sections have been compared
to an order alpha_s squared perturbative QCD calculation.
In addition, both the three- and four-jet cross sections have
been compared with leading-logarithmic parton-shower Monte Carlo
models, with and without multi-parton interactions.
|
Strong Interactions |
"Previously submitted with the wrong title of ""Measurements of (anti)deauteron....""" |
halina@mail.desy.de |
| 116 |
Sudhir Malik |
Construction of the CMS Forward Pixel Detector |
At the core of CMS all-silicon tracker is the Pixel Detector. It provides fine granularity for the charged track reconstruction with 3D-space measurements and resolution on the order of ten microns. It comprises of two pixel disks on either side of the interaction region and three barrel pixel layers. The disks are called the Forward Pixel detector and are being assembled at Fermilab, U.S.A. The detector modules for the disks consist of eighteen million pixels. After successful completion of a small slice of this detector for the 2007 pilot physics run of the LHC, we are on our way to finish the assembly and construction of the four disks, for a scheduled insertion into CMS in 2008. An overview of the detector and its latest construction status will be presented |
Detectors and Data Handling |
|
malik@fnal.gov |
| 117 |
Neeti Parashar |
Geometry Simulation and Physics with the CMS Forward Pixel Detector |
The Forward Pixel Detector of CMS is an integral part of the Tracking system, which would play a key role in addressing the full physics potential of the collected data. It has a very complex geometry that encompasses multilayer structure of its detector modules. This presentation will describe the development of geometry simulation for the Forward Pixel Detector. A new geometry package has been developed, which uses the detector description database (DDD) interface for the XML (eXtensive Markup Language) to GEANT simulation. This is necessary for digitization and GEANT4 reconstruction software for tracking. The expected physics performance shall also be discussed. |
Detectors and Data Handling |
|
neeti@fnal.gov |
| 118 |
A. Drago, A. Lavagno |
Isospin dependence of quark deconfinement in heavy ion collisions |
We study the transition from hadronic matter to a mixed phase of quarks and hadrons at high baryon and isospin densities, reached in heavy-ion collisions. We study in detail the formation of a drop of quark matter in the mixed phase and we discuss the effects on the quark drop nucleation probability of the finite size and finite time
duration of high density region [1]. We apply this technique to the interpretation of the recent analysis of heavy ion scattering at
energies of 2-10 A GeV [2], indicating a significant reduction of the nuclear incompressibility. We fix the parameters
of the MIT bag model to reproduce the observed reduction of the incompressibility.
Finally, we discuss the implications of our
results for the structure and formation of compact stars [4,5].
[1] M. Di Toro, A. Drago, T. Gaitanos, V. Greco, A. Lavagno, Nucl. Phys. A 775, 102 (2006).
[2] V.N. Russkikh, Yu.B. Ivanov, Phys. Rev. C 74, 034904 (2006).
[3] L. Bonanno, A. Drago, A. Lavagno, in preparation.
[4] Z. Berezhiani, I. Bombaci, A. Drago, F. Frontera, A. Lavagno, Astrophys. J. 586, 1250 (2003).
[5] A. Drago, A. Lavagno, I. Parenti, astro-ph/0512652, Astrophys. J. in press. |
High-Energy Nuclear Physics |
|
andrea.lavagno@polito.it |
| 119 |
Mario Campanelli (CDF coll.) |
Measurement of heavy flavor production associated with a photon |
We report on a study of events containing a photon and heavy flavor
jets in data taken by the CDF experiment at the Fermilab Tevatron
collider. This measurement is performed using a dedicated dataset that
exploits the silicon vertex trigger to enrich the b-jet content, and
therefore lower the photon threshold.
Results are compared to QCD predictions as a function of relevant
kinematic variables. |
Strong Interactions |
|
mario.campanelli@cern.ch |
| 120 |
Sandro De Cecco - INFN Rome Italy - CDF Collaboration |
Measurement of the Z boson associated production with Heavy Flavor jets at CDF |
Production of Z boson in association with b or c quark is an important background to Higgs
searches at the Tevatron collider and an interesting test ground for QCD calculations.
We will present this measurement in two approaches using different b-tagging techniques:
a traditional secondary vertex b-tag and a newly developped neural net tagging algorithm.
In the latter a sophisticated vertexing algorithm is used to select all the displaced vertices and
charged particles produced in the decays of heavy flavor hadrons present in b and c quark jets.
All avaliable information on jet tracks and vertices is used in a neural net to enhance the b to light-jet and b to c-jet separation, the final discriminant variable is then fitted to measure
the heavy flavour fractions. |
Strong Interactions |
|
sandro.dececco@roma1.infn.it |
| 121 |
Michal Kreps (CDF Collaboration) |
Latest Results on B-hadron Spectroscopy from CDF |
We review the latest results on the spectroscopy of B-hadrons from 1 fb$^{-1}$ of CDF data. The measurements are performed with fully reconstructed B-hadron decays collected with the CDF II detector at $\sqrt{s} = 1.96$ TeV. The main highlights are the results on the orbitally excited $B$ and $B_s$ mesons and observation of the new B-baryons.
|
Flavour Physics and CP Violation |
|
kreps@ekp.uni-karlsruhe.de |
| 122 |
A. Donini, E. Fernandez-Martinez, P. Migliozzi, L. Scotto Lavinia, M. Selvi, F. Terranova and T. Tabarelli de Fatis |
Neutrino hierarchy from atmospheric and beta beam neutrinos with high density magnetized detectors |
High density magnetized detectors are well suited to exploit the outstanding purity and intensities of novel neutrino sources like Neutrino Factories and Beta Beams. They can also provide independent measurements of leptonic mixing parameters through the observation of atmospheric muon-neutrinos. In this paper, we discuss the combination of these observables from a multi-kton iron detector and a high energy Beta Beam; in particular, we demonstrate that even with moderate detector granularities the neutrino mass hierarchy can be determined for $\theta_{13}$ values greater than 4$^\circ$.
|
Neutrino Physics |
|
tommaso.tabarelli@mib.infn.it |
| 123 |
KLOE Collaboration |
KLOE measurement of the charged kaon lifetime |
The charged K lifetime is an experimental input to the
determination of Vus. The present fractional uncertainty is about 0.2%,
however the available data show large discrepancies between the
measurements done using charged kaon decays in-flight and at-rest.
At KLOE two different methods have been developed: one based on
the measurement of the charged kaon decay length
and the other based on its decay time.
Both methods allow us to reach accuracies at the few per mil
level and together allow us to assess part of the systematic uncertainty.
Efficiency and resolution functions are measured directly on data
using an independent control sample.
The measurement of the charged kaon lifetime, based on about 260 pb-1
of the total integrated luminosity (2.5 fb-1), will be presented.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 124 |
KLOE Collaboration |
KLOE measurement of the charged kaon absolute semileptonic BR's |
The most precise evaluation of the CKM matrix element |Vus| is obtained
using semileptonic decays of the kaons.
At KLOE the measurement of the branching ratios for the charged K
semileptonic decays uses four independent samples tagged by the
following kaon decays:
K+ -> mu2, K+ -> pi2, K- -> mu2, and K- -> pi2.
Using 410 pb-1 of total integrated luminosity (2.5 fb-1),
about 60 million tag decays have been identified and
divided into the four tag samples.
This redundancy allows us to keep under control the systematic
effects due to the tag selection.
The BR is evaluated separately for each tag sample, dividing by
the number of tag counts and correcting for acceptances. The latter are
obtained from MC simulations. Corrections are applied to account for data-MC
differences in tracking and clustering.
K+-e3 and K+-mu3 decays are selected using kinematical cuts in the kaon rest
frame and time of flight particle identification.
The measurement of these BR's will be presented.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 125 |
KLOE Collaboration |
KLOE measurement of the absolute BR(K+ -> pi pi0) |
A new precise measurement of the absolute branching ratio
BR(K+ -> pi+ pi0 (gamma)) has an important impact on the
world average of the charged kaon semileptonic BR's since
the NA48, ISTRA+ and E865 experiments use this two-body decay
in the normalization sample.
At KLOE a pure K+ beam is tagged by the recostruction of the
K- -> mu- nu decays. The signal counting is given by a fit
to the distribution of the momentum of the charged decay particle
in the kaon rest frame assuming the pion mass.
The shapes of the signal and of the backgrond (K+ -> mu nu and
three-body decays) are obtained from data control samples and MC.
The efficiency is measured directly on data using an
independent control sample.
The measurement of the BR(K+ -> pi+ pi0 (gamma)), based on about 260 pb-1
of the total integrated luminosity (2.5 fb-1), will be presented.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 126 |
B. Pinto (Universidade de Lisboa), S. Marti i Garcia (IFIC-Valecnia, UV-CSIC), J. Schieck (MPI Muenchen) |
Alignment data streams for the ATLAS Inner Detector |
The ATLAS experiment uses a complex trigger strategy to be able to achieve the necessary Event Filter rate output, making possible to optimize the storage and processing needs of these data. These needs are described in the ATLAS Computing Model which embraces Grid concepts. The output coming from the Event Filter will consist of four main streams: the physical stream, express stream, calibration stream, and a diagnostic stream. The calibration stream will be transferred to the Tier-0 facilities which will provide the prompt reconstruction of this stream with a minimum latency of 8 hours, producing calibration constants of sufficient quality to permit a first-pass processing. The Inner Detector community is developing and testing an independent common calibration stream selected at the Event Filter after track reconstruction. It is composed of raw data, in byte-stream format, contained in ROB's with hit information of the selected tracks, and it will be used to derive and update a set of calibration and alignment constants after every fill. This option was selected because makes use of the Byte Stream Converter infrastructure and possibly give us a better bandwidth usage and storage capability's. Processing is done using specialized algorithms running in Athena framework in dedicated Tier-0 resources, and the alignment constants will be stored and distributed using the COOL conditions database infrastructure. The work is addressing in particular the alignment requirements, the needs for track and hit selection and the timing issues. |
Detectors and Data Handling |
oral presentation |
Salvador.Marti@ific.uv.es |
| 127 |
M.J. Costa on behalf of the ATLAS collaboration |
Commissioning of the ATLAS offline software with cosmic rays |
The ATLAS experiment of the LHC is now taking its first data by collecting cosmic ray events. The full reconstruction chain including all sub-systems (inner detector, calorimeters and muon spectrometer) is being commissioned with this kind of data for the first time.
Specific adaptations to deal with particles not coming from the interaction point and not synchronized with the readout clock were needed. Data decoders and the infrastructure to deal with conditions data as those coming from the data acquisition configuration, detector control system, calibration and alignment corrections were developed and validated as well.
Detailed analysis are being performed in order to provide ATLAS with its first alignment and calibration constants and to study the combined muon performance. Combined monitoring tools and event displays have also been developed to ensure the good data quality.
A simulation of cosmic events according to the different detector and trigger setups has also been provided to verify it gives a good description of the data.
|
Detectors and Data Handling |
|
Maria.Jose.Costa@cern.ch |
| 128 |
P. Miyagawa (University of Manchester, UK), S. Marti i Garcia (IFIC-Valecnia, UV-CSIC, Spain), J. Schieck (MPI Muenchen, Germany) |
Software representation of the ATLAS magnetic field |
The ATLAS solenoid produces a magnetic field which enables the Inner Detector to measure track momentum by track curvature. This solenoidal magnetic field was measured using a rotating-arm mapping machine and, after removing mapping machine effects, has been understood to the 0.05% level. As tracking algorithms require the field strength at many different points, the representation of this magnetic field in Athena (the ATLAS offline software framework) can have a significant impact on the processing time for these algorithms. We review the field models and mathematical techniques used to decouple machine effects from real field features and evaluate the performance of different field representations within Athena. |
Detectors and Data Handling |
oral presentation & on behalf of the ATLAS collaboration |
"Salvador.Marti@ific.uv.es,schieck@mppmu.mpg.de" |
| 129 |
KLOE Collaboration |
Preliminary measurement of BR(ke2)/BR(kmu2) at KLOE |
The measurement of the ratio of Ke2 and Kmu2 branching fractions
is extremely well known within the Standard Model, in which
muon-electron universality holds. In SUSY extensions the presence of
Lepton Flavour Violating sources can produce non-universal terms.
Therefore the measurement of the ratio BR(ke2)/BR(kmu2) is very important in
probing mu-e universality and the presence of physics beyond the SM.
We present a preliminary measurement of the ratio of the purely leptonic branching
ratios of the charged kaons, BR(ke2)/BR(kmu2), using a sample of about 2 fb-1 of data
acquired with the KLOE detector at the Frascati Phi-factory DAFNE.
|
Flavour Physics and CP Violation |
|
giorgio.capon@lnf.infn.it |
| 130 |
S. Marti i Garcia, S. Gonzalez-Sevilla (IFIC-Valencia, UV-CSIC, Spain), J. Schieck, T. Goetffert (MPI Muenchen, Germany) |
Track based alignment of the ATLAS inner detector |
It is foreseen that the Large Hadron Collider will start its operations and collide proton beams during November 2007. ATLAS is one of the four LHC experiments currently under preparation. The alignment of the ATLAS tracking system is one of the challenges that the experiment must solve in order to achieve its physics goals. The tracking system comprises two silicon technologies: pixel and microstrip plus a transition radiation detector. The alignment of the system requires a determination of more than 36000 degrees of freedom. The precision required for the most sensitive coordinate of the devices is of the order of few microns. This precision should be attained with a track based alignment and from the application of complex alignment algorithms. They require an extensive CPU and memory usage as large matrix inversion and many iterations algorithms are used. The alignment algorithms have been already exercised on several challenges as for instance real data ones: Combined Test Beam plus Cosmic Ray runs (at the surface and in the pit) as well with large scale computing simulation of physics samples. This note reports on the methods, their computing requirements and its preliminary results. |
Detectors and Data Handling |
oral presentation & on behalf of the ATLAS collaboration |
"Salvador.Marti@ific.uv.es,schieck@mppmu.mpg.de" |
| 131 |
C. Schmitt on behalf of the ATLAS Inner Detector Offline Commissioning group |
Commissioning of the ATLAS Inner Detector with cosmic rays |
The inner detector of the ATLAS experiment is in the process of being
commissioned using cosmic ray events. First tests were performed in
the SR1 assembly hall at CERN with both barrel and endcaps for all
different detector technologies (pixels and microstrips silicon
detectors as well as straw tubes with additional transition radiation
detection). Integration with the rest of the ATLAS sub-detectors is
now being done in the ATLAS cavern.
The full software chain has been set up in order to reconstruct and
analyse this kind of events. Final detector decoders have been
developed, different pattern recognition algorithms and track fitters
have been validated as well as the various alignment and calibration
methods. The infrastructure to deal with conditions data coming from
the data acquisition, detector control system and calibration runs
has been put in place, allowing also to apply alignment and calibration
constants.
The software has also been essential to monitor the detector
performance during data taking. Detector efficiencies, noise
occupancies and resolutions have been studied in detail and compared
with those obtained from simulation. |
Detectors and Data Handling |
|
Christian.Schmitt@cern.ch |
| 132 |
Sofia Vallecorsa on behalf of the CDF collaboration |
Measurement of the b-bbar jet cross section at CDF |
We present a $b \bar b$ jet cross section measurement based on about 260
$pb^{-1}$ of data, collected by CDF Run II until September 2004.
The analysis strongly relies on the CDF detector good tracking capabilities both at trigger level,
as data is selected requiring two displaced tracks at Level 2,
and offline, since b-tagging is performed reconstructing secondary vertices inside the jet.
The differential cross section is measured in the central region of the
detector,
focusing in particular on the study of the $b \bar b$
$\Delta \phi$ correlation, which gives information on the
relative contribution of different production meachanisms.
Results are corrected to the hadron level and compared to Leading Order (Pythia and Herwig) and Next-to-Leading Order (MC@NLO) Montecarlo.
|
Strong Interactions |
|
sofia.vallecorsa@cern.ch |
| 133 |
W. Vandelli on behalf of the DREAM Collaboration |
Cherenkov Light Contribution in Lead Tungstate Crystals |
Results of detailed measurements of the Cherenkov light yield from lead tungstate (PbWO4) crystals are presented. A single crystal as well as a small homogeneous calorimeter (ECAL), consisting of 19 PbWO4 crystals, were exposed to electrons, muons and pions in the H4 beam at CERN. It turns out that a significant fraction of the detected light is not the result of scintillation processes, but rather of the Cherenkov mechanism. This can be assessed from the analysis of both the angular dependence of the signals and their time structure. Detailed studies of the ECAL signals, corroborated by the measurements taken with the Dual-Readout Calorimeter (DREAM) backing up the ECAL during beam tests, show that is possible to estimate the independent contributions of scintillation and Cherenkov light. This information makes it possible to account for one of the dominant sources of fluctuations in hadronic showers and thus to achieve a significant improvement in hadronic calorimetry performance. |
Detectors and Data Handling |
|
wainer.vandelli@cern.ch |
| 134 |
KLOE Collaboration |
New Measurements of the e+e- -> pi+pi-gamma Cross Section and |
The KLOE experiment at the phi factory DAPHNE is using ISR to measure
sigma(e+e- -> pi+pi-gamma) and sigma(e+e- -> mu+mu-gamma),
with an absolute
normalisation obtained from Bhabha scattering.
The pi+pi-gamma events are obtained with two different selection criteria:
(a) requiring the photon emission at small angles (SA)
(b) detecting the photon at large angles in the calorimeter (LA).
With the two samples we cover the complete range of 2m_pi < sqrt{s'} = M_{pipi} < m_phi.
Using a theoretical radiator function H(s) we extract the pion form factor |F_pi|^2 and
obtain the two-pion contribution to a_mu^{had}.
An alternative way to obtain |F_pi|^2 is via the ratio of
sigma(e+e- -> pi+pi-gamma) over sigma(e+e- ->mu+mu-gamma).
Results to be presented come from the analysis of 240 pb^{-1} collected in 2002,
with very small statistical error (~0.1%) and improved systematic
uncertainties (~1\%). Furthermore, using a run of
200 pb^{-1} of data taken at sqrt{s}=1 GeV, we can minimize the backgrounds due to
resonant processes.
|
High-Energy Electroweak Physics |
|
giorgio.capon@lnf.infn.it |
| 135 |
Michel Sorel for the MiniBooNE collaboration |
MiniBooNE, part 2: First results of the muon-to-electron
neutrino oscillation search |
The "blind" oscillation analysis performed, where all analysis selections and fitting procedures are determined before candidate electron neutrino events are examined, is described. First MiniBooNE
neutrino oscillation results of electron neutrino appearance in a muon neutrino beam from this analysis are presented, and implications of the results are discussed. Finally, an outlook of MiniBooNE's next steps in light of these results is given. |
Neutrino Physics |
This talk and that of Byron Roe are companion talks on MiniBooNE. We request this talk be immediately preceded by Roe's talk on the MiniBooNE experiment and data analysis. |
sorel@fnal.gov |
| 136 |
tara ohmdeiy |
atomic energy elements &property |
NUCLEAR ENERGY(PROPERTY OF ELEMENT,REACTION) Keywords :atoms ,reaction ,action ,energy , radio active.
E-mail: tara_ahmadi_smart@yahoo.com
structure of atoms& nuclear forces
nucleus are proton & neutron mp=1/6729*10ª kj A=-27
proton has e=1/60*10ª C A=-19 &it quantum number =½
the mass of neutron are more than proton Mn=1/6750*10ª A=-27
nuclear forces
1.nuclear forces attractive atoms & is more than electrostatic or gravity.
2.nuclear force is between short distances & if this distance will more than normal state will zero fast.
3.nuclear force is between two nucleon(this force is between two state : neutron & proton, two neutron& proton ).
we can find this force by equation according to electrostatic force, distance between two particle is rather 2Ŗ=2/4×10ª n A=-15
so this is F=kq²/r²=(9×10³•³Nm²/c²)(1/6×10¹º´³•³)²÷(2/4×10¹º´³´²m)²=40N (´=+)
potential energy of proton is the function distance until center of atom r>R , potential energy from colon's repulsive between proton& nucleus with Ze internal energy.
if the potential energy will less fast mean the nuclear force not available.
this force must between short & constant distances means this is microscopy , if the particle come near the nucleus ;this nucleus will like + particle & we can decide this action according to Electromagnetic force.
once usage a bout this action is full of nuclear energy , this is a reason for build a normal state & say why nucleon binding energy in normal mass till heavy mass nuclear are without number of nucleus.
this reason of full energy is each nucleus by nuclear energy only can action with nearest particles ( in it we have 30 nearest particles).
Conservation energy
Binding energy
when atoms emitted , it need more energy because is between them violent nuclear energy & when build a nucleus , we have many free energy , this energy is Binding energy.
According to special relativity ; we can say even time nuclear energy will less than when are behind an other .
general nuclear mass must will less the add of protons & neutrons that mean A Z Mn
is nuclear mass with atomic number A=Z+N,
so Mnc²
| High-Energy Nuclear Physics |
no |
tara_ahmadi_smart@yahoo.com |
|
| 137 |
G.Bozzi, B.Jager, C.Oleari, D.Zeppenfeld |
Next-to-leading order QCD corrections to W+ Z and W- Z production via vector-boson fusion. |
We present the calculation of the next-to-leading order QCD corrections to electroweak p p -> e+ nu_e mu+ mu- jj and p p -> e- nubar_e mu+ mu- jj production at the CERN LHC in the form of a fully flexible parton-level Monte Carlo program. The QCD corrections to the total cross sections are modest, changing the leading-order results by less than 10%. At the Born level, the shape of kinematic distributions can depend significantly on the choice of factorization scale. This theoretical uncertainty is strongly reduced by the inclusion of the next-to-leading order QCD corrections.
|
Strong Interactions |
"This is the last of three papers devoted to NLO QCD corrections to vector boson pair production via vector boson fusion. I will present results from the other two papers as well. hep-ph/0603177, hep-ph/0604200, hep-ph/0701105. hep-ph/0701105" |
giuseppe@particle.uni-karlsruhe.de |
| 138 |
G.Bozzi, B.Fuks, M.Klasen |
Threshold Resummation for Slepton-Pair Production at Hadron Colliders. |
We present a first and extensive study of threshold resummation effects for supersymmetric (SUSY) particle production at hadron colliders, focusing on Drell-Yan like slepton-pair and slepton-sneutrino associated production. After confirming the known next-to-leading order (NLO) QCD corrections and generalizing the NLO SUSY-QCD corrections to the case of mixing squarks in the virtual loop contributions, we employ the usual Mellin N-space resummation formalism with the minimal prescription for the inverse Mellin-transform and improve it by resumming 1/N-suppressed and a class of N-independent universal contributions. Numerically, our results increase the theoretical cross sections by 5 to 15% with respect to the NLO predictions and stabilize them by reducing the scale dependence from up to 20% at NLO to less than 10% with threshold resummation.
|
Physics Beyond the Standard Model |
I will present results from this paper (hep-ph/0701202) as well as from a preceding one about qt-resummation (hep-ph/0603074) and a new one about joint resummation which is about to be finsihed. The three papers deal with slepton pair and slepton-sneutrino associated production at hadron colliders. |
giuseppe@particle.uni-karlsruhe.de |
| 139 |
Matthew Wing (UCL) on behalf of Cambridge, Imperial, Manchester, RHUL, UCL |
Data acquisition systems for future calorimetry at the ILC |
A data acquisition system is described which will be used for the next generation of prototype calorimeters for the International Linear Collider and could also be used for the final system. The design is sufficiently generic such that it should have applications elsewhere, be they other ILC detectors or within High Energy Physics in general: e.g. this could be applied to LHC upgrade apparatus. The concept of moving towards a "backplaneless" readout is pursued. A strong under-pinning thread here is to attempt to make use of commercial components and identify any problems with this approach. Therefore the system should be easily upgradable, both in terms of ease of acquiring new components and competitive prices. The conceptual design, both hardware and software,
of the data acquisition system for the ILC calorimeter will be discussed. Results and tests already done will then be shown indicating both the potential and limitations of the approach.
|
Detectors and Data Handling |
|
mw@hep.ucl.ac.uk |
| 140 |
Byron Roe for the MiniBooNE collaboration |
The MiniBooNE experiment, part 1: Experiment and Data Analysis |
The MiniBooNE experiment and the data analysis
are described. Topics include experimental
setup, apparatus response, calculation of
neutrino and event flux, event reconstruction,
particle identification algorithms,
systematic errors, and charged current quasi-elastic cross sections.
|
Neutrino Physics |
This talk and that of Michel Sorel are companion talks on MiniBooNE. We request this talk be first followed by Michel's talk on MiniBooNE results. |
byronroe@umich.edu |
| 141 |
Guskov Alexey |
Pion polarisability measurement at COMPASS. |
The electromagnetic structure of pions is probed in ${\pi}^{-}+(A,Z)\to {\pi}^{-}+(A,Z)+\gamma$
Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric
(${\alpha}_{\pi}$) and the magnetic
(${\beta}_{\pi}$) polarizabilities, that depend on the rigidity of pion's
internal structure as a composite particle. Values for pion polarizabilities
can be extracted from the comparison of the
differential cross section for scattering of pointlike pions with
the measured cross section. The pion polarizability measurement was performed
with a ${\pi}^{-}$ beam of 190~GeV .
The high beam intensity, the good spectrometer
resolution, the high rate capability, the high acceptance and the possibility
to use pion and muon beams, that are unique to the COMPASS
experiment provide the tools to measure precisely the pion polarizabilities
in the Primakoff reaction.
The precise tracking system, electromagnetic and hadron calorimeters
provide neccessary conditions for Primakoff events selection and background
suppression. Most of the statistics was collected with a lead target,
along with smaller samples using carbon and copper.
The COMPASS result is compared to predictions from various models:
$chiPT$,dispersion sum rules, QCD sum rule, lattice calculations.
|
Strong Interactions |
|
guskov@mail.cern.ch |
| 142 |
Guskov A. on behalf of COMPASS collaboration |
Pion polarisability measurement at COMPASS. |
The electromagnetic structure of pions is probed in ${\pi}^{-}+(A,Z)\to {\pi}^{-}+(A,Z)+\gamma$
Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric
(${\alpha}_{\pi}$) and the magnetic
(${\beta}_{\pi}$) polarizabilities, that depend on the rigidity of pion's
internal structure as a composite particle. Values for pion polarizabilities
can be extracted from the comparison of the
differential cross section for scattering of pointlike pions with
the measured cross section. The pion polarizability measurement was performed
with a ${\pi}^{-}$ beam of 190~GeV .
The high beam intensity, the good spectrometer
resolution, the high rate capability, the high acceptance and the possibility
to use pion and muon beams, that are unique to the COMPASS
experiment provide the tools to measure precisely the pion polarizabilities
in the Primakoff reaction.
The precise tracking system, electromagnetic and hadron calorimeters
provide neccessary conditions for Primakoff events selection and background
suppression. Most of the statistics was collected with a lead target,
along with smaller samples using carbon and copper.
The COMPASS result is compared to predictions from various models:
$chiPT$,dispersion sum rules, QCD sum rule, lattice calculations.
|
Strong Interactions |
|
guskov@mail.cern.ch |
| 143 |
KLOE Collaboration |
Measurement of the eta mass at Kloe |
The KLOE collaboration has performed a measurement of the eta mass
using the decay phi => eta gamma, eta => gamma gamma.
The two most precise measurements available from the NA48 collaboration
and GEM collaboration shows a discrepancy of about 8 sigma one from each other,
indicating the need of a further measurement in order to clarify the situation.
In this presentation we will show the new measurement obtained by using kinematic
constraints on the 3 photons event and the careful evaluation of all the systematics
that can affect the measurement.
The comparison with the previous measurements will be shown. |
Strong Interactions |
2nd suggested session: Flavour Physics and CP Violation |
giorgio.capon@lnf.infn.it |
| 144 |
KLOE Collaboration |
Study of the phi=>eta pi0 gamma decay at Kloe |
The KLOE experiment has collected 2.5 fb-1 at the peak of the phi
resonance, at the e+e- collider DAphNE in Frascati.
The data collected in the 2001-2002 running period, corresponding to about
450 pb-1, have been used to investigate the properties of the light
scalar meson a0(980), whose structure is still controversial (q qbar, 4
quark state, or K Kbar molecule).
The a0 meson has been observed through the decay chains phi(1020)=>
a0 gamma, a0=>eta pi0 with eta=>gammagamma and
eta=>pi+pi-pi0.
The Br() has been measured, and the etapi0
invariant mass spectra have been fitted with two different theoretical
approaches, to obtain the relevant parameters of the resonance, the mass
and the couplings g_phia0gamma, g_a0etapi0 and g_a0KKbar.
The results are compared to the SU(3) expectations for the possible
structures of the meson. |
Strong Interactions |
|
giorgio.capon@lnf.infn.it |
| 145 |
KLOE Collaboration |
Search for the phi=> f0/a0 gamma=> KS KS gamma decay at Kloe |
One possible decay mode for the f0(980),a0(980) scalar mesons is into
K0 K0bar. At Kloe f0 or a0 are produced via the radiative decay phi=> f0/a0 + gamma
with the resulting K0barK0 mesons produced in a symmetric state
JPC=0++. No previous measurement of this decay mode exists. The
expected branching ratio for this channel with Kaon Loop
models is of order 10-8.
KLOE looks for KS KS gamma final state events, with both KS
decaying in pi+pi-. Results are presented with the full KLOE statistics.
|
Strong Interactions |
2nd suggested session: Flavour Physics and CP Violation |
giorgio.capon@lnf.infn.it |
| 146 |
KLOE Collaboration |
Determination of the BR ratio R_phi=BR(phi => eta_prime gamma)/BR(phi => eta gamma) at Kloe |
We present the most accurate determination to date of the ratio
R_phi=BR(phi => eta_prime gamma)/BR(phi => eta gamma).
The result has been obtained by studying the radiative decays
phi => eta_prime gamma and phi => eta gamma in the final states
pi+pi- 7 gamma's and 7 gamma's respectively, in a sample of
about 10+9 phi mesons produced at the Frascati phi-factory.
We obtain R_phi=(4.77 +- 0.09 stat +- 0.19 syst) 10-3 from which
we derive BR(phi => eta_prime gamma)=(6.20 +- 0.11 stat +- 0.25 syst) 10-5.
In the hypothesis of no gluonium content we extract the pseudoscalar mixing angle in the
quark-flavor basis phi_P=(41.4 +- 0.3 stat +- 0.7 syst +- 0.6 th)\circ.
Combining the value of R_phi with other constraints, we
estimate the gluonium fractional content of eta_prime meson
as Z2 = 0.14 +- 0.04 and the mixing angle phi_P = 39.7 +- 0.7 degrees.
|
Strong Interactions |
|
giorgio.capon@lnf.infn.it |
| 147 |
KLOE Collaboration |
Study of the eta => 3pi decay Dalitz plot at Kloe |
We have studied the process eta=> 3 pi at the Frascati phi factory,
by looking at nearly 17 millions decays of eta mesons produced via
the radiative process phi=>eta gammma. The dynamics of the decay
has been studied using the Dalitz plot technique, obtaining the most accurate
determination to date of the parameters of the Dalitz plot expansion
in the pi+pi-pi0 final state and a new determination of the eta=>
3pi0 quadratic slope. Results can be compared to chiral perturbation theory
predictions in order to extract information on light quark mass ratios.
|
Flavour Physics and CP Violation |
2nd suggested session: Strong Interactions |
giorgio.capon@lnf.infn.it |
| 148 |
KLOE Collaboration |
Study of the two pions decay of the f0(980) at Kloe |
The KLOE experiment has collected 2.5 fb-1 of e+e- collisions at center of
mass energy around the phi mass. Phi radiative decays are used to produce
large statistical samples of light scalar mesons. The search for the f0(980)
in dipion final states, with the 450 pb-1 acquired in 2001/2002, has been
completed.
The f0(980)-->pi+pi- is searched for as a deviation from the expected
ISR+FSR contributions in pi+pi-gamma events with photons at large angle;
a clear scalar signal is observed in the pi+pi- invariant mass and in the
charge asymmetry distributions.
The reaction e+e- --> pi0pi0gamma has been studied by performing a Dalitz
plot analysis of around 145 pb-1 with beam energies between 1019.7 and
1019.8 MeV. The high statistical sample of around 130,000 events is
described by the not resonant rho --> omega pi0 mediated production
and the phi --> f0(980) gamma decay mechanism.
These data samples are used to investigate the properties of f0(980) by
studying their invariant mass shapes or the event density in the Dalitz
plot, thus shading light on the controversial structure of these particles.
A possible contribution due to sigma(600) is also exploited. In order to
discriminate between models, data have been fit with different theoretical
approaches. For each of them we extract the f0(980) mass and its coupling
to KK, pipi and to the phi meson. The Kaon Loop model gives a stable
framework to describe both final states. A high coupling of the f0(980) to
kaons and to the phi is found, enforcing the interpretation of its nature
as a 4-quark state.
|
Strong Interactions |
|
giorgio.capon@lnf.infn.it |
| 149 |
Jean-Marc Le Goff on behalf of the COMPASS collaboration |
Measurement of gluon polarization at COMPASS |
One of the main aim of the COMPASS collaboration at Cern is the measurement of the gluon polarization inside the nucleon. This is done through the measurement of the double spin asymmetry of the photon-gluon-fusion process in the scattering of 160 GeV polarized muons on polarized deuterons. This process is tagged either by open charm production or by the production of a pair of high pt hadrons. The first method is very clean but it suffers from limited statistical accuracy, Delta G/G (x=0.15)= 0.57 +- 0.41(stat) +- 0.17(syst). The second method provides good statistical accuracy and, using events at low Q2, it provides a result : Delta G/G (x=0.09)= 0.016 +- 0.058(stat) +- 0.055(syst). This result disfavors large values of the gluon spin contribution to the nucleon spin, Delta G, which is the integral of Delta G(x).
|
Strong Interactions |
|
jmlegoff@cea.fr |
| 150 |
B.El-Bennich, A.Furman, R.Kaminski, L.Lesniak, B.Loiseau |
CP violation and final state interactions in B --> K pi pi decays |
We study CP violation and final state interactions between pairs of pseudoscalar
mesons in three body B+, B-, B0 and antiB0 decays into K pi pi system. The weak transition amplitudes consist of two terms: the first part
obtained in QCD factorization and the second being a long - distance charming penguin contribution. In the S- wave, the rescattering or the transition amplitudes between two pions are described by a unitary coupled channel model in which all the scalar- isoscalar resonances appear as poles of the meson-meson amplitudes. Interesting interference effects between the
f0(980) and rho(770) resonances are found. A good global fit to the available BaBar and Belle data is performed using four complex charming penguin
parameters in the S- and P- waves. The data consist of 204 data points describing the pi+ pi- effective mass and angular distributions and 18 observables which include branching fractions, direct CP- violating asymmetries for the charged B decays as well as time- dependent CP asymmetries. The observed large direct
CP- asymmetry for B+- --> rho(770) K+- decays is well reproduced [1].
Extentions of the above approach to include interactions between pions and kaons
in the final states are being currently considered.
Reference:
[1] B. El-Bennich, A. Furman, R. Kaminski,
L. Lesniak and B. Loiseau,
Interference between f0(980) and rho(770) resonances in B --> pi+ pi- K decays,
Phys. Rev. D 74 (2006) 114009.
|
Flavour Physics and CP Violation |
|
Leonard.Lesniak@ifj.edu.pl |
| 151 |
NA48 Collaboration |
Recent results from NA48/2 on Ke4 decays and interpretation in term of pi-pi scattering lengths |
The NA48/2 experiment at the CERN SPS has collected about 10**6 K± decays into pi+ pi- e± ν (Ke4) in 2003 and 2004. The analysis of a partial sample of ~500000 such events allows a precise measurement of the decay parameters. The form factors of the reaction and their dependence with dipion and dilepton masses have been measured. Thanks to a sizeable acceptance at large Mpipi and the very good resolution of the NA48 detector, a high sensitivity to the pi-pi scattering lengths a00 and a02 is achieved. These almost model independent measurements can be confronted with the predictions from different calculations, in particular within the framework of Chiral Perturbation Theory. |
Strong Interactions |
|
cristina.lazzeroni@cern.ch |
| 152 |
CALICE Collaboration |
First CALICE Analogue HCAL results from CERN test beam data |
A prototype hadronic calorimeter for an ILC detector was installed and tested during summer 2006 at the CERN SPS facilities. The detector, consisting of about 500 scintillator tiles, read out via Silicon photomultipliers, was commissioned and calibrated. Data were collected with electron and hadron beams in the energy range 6 to 80 GeV. A first part of the analysis foxuses on the electromagnetic shower reconstruction. Though somewhat simpler than hadronic shower reconstruction, this analysis is crucial to demonstrate the quality of the calibration and detector understanding through comparison with Monte Carlo simulations.
This contribution focuses on the commisioning of the Analogue HCAL detector, the calibration procedure and performance, and on the first results of the electromagnetic shower analysis. |
Detectors and Data Handling |
|
drw1@cam.ac.uk |
| 153 |
NA48 collaboration |
NA48/2 Final results on charged semileptonic kaon decays and Vus |
Measured ratios of decay rates for ${\cal R}_{K e 3/K2\pi}$, ${\cal R}_{K \mu 3/ K2\pi}$ and ${\cal R}_{K \mu 3 / Ke3}$ are presented. These measurements are based on $K^\pm$ decays collected in a dedicated run in 2003 by the NA48/2 experiment at CERN. The results obtained are ${\cal R}_{K e 3 / K2\pi}=0.2496\pm0.0009 (stat)\pm 0.0004 (syst)$ and ${\cal R}_{K \mu 3 /K2\pi} = 0.1637\pm 0.0006 (stat)\pm 0.0003(syst)$. Using the PDG average for the $K^\pm \rightarrow\pi^\pm \pi^0$ normalisation mode, both values are found to be larger than the current values given by the Particle Data Book and lead to a larger magnitude of the $|V_{us}|$ CKM element than previously accepted. When combined with the latest Particle Data Book value of $|V_{ud}|$, the result is in agreement with unitarity of the CKM matrix. In addition, a new measured value of ${\cal R}_{K \mu 3 / K2\pi} = 0.656\pm 0.003(stat)\pm 0.001(syst)$ is compared to the semi-empirical predictions based on the latest form factor measurements. |
High-Energy Electroweak Physics |
|
cristina.lazzeroni@cern.ch |
| 154 |
NA48 collaboration |
Testing the lepton universality with K->l nu decays |
The ratio $R_K = \Gamma(K^{\pm}\to e^{\pm}\nu) / \Gamma(K^{\pm}\to \mu^{\pm}\nu) $ provides a very powerful probe for the weak interactions structure. This ratio of decay rates is calculated with very high precision within the Standard Model but corrections due to the presence of New Physics could be as high as 3\%. The data obtained by the NA48 experiment in two years of data taking at the CERN SPS accelerator has been analyzed. The obtained result for $R_K$ is two times more precise than the world average but is still insufficient to probe the existence of physics Beyond the Standard Model. A new run in 2007, aimed for a sub-percent precision measurement of $R_K$, has been proposed and approved. |
Physics Beyond the Standard Model |
|
cristina.lazzeroni@cern.ch |
| 155 |
NA48 collaboration |
Testing the lepton universality with K->l nu decays |
The ratio $R_K = \Gamma(K^{\pm}\to e^{\pm}\nu) / \Gamma(K^{\pm}\to \mu^{\pm}\nu) $ provides a very powerful probe for the weak interactions structure. This ratio of decay rates is calculated with very high precision within the Standard Model but corrections due to the presence of New Physics could be as high as 3\%. The data obtained by the NA48 experiment in two years of data taking at the CERN SPS accelerator has been analyzed. The obtained result for $R_K$ is two times more precise than the world average but is still insufficient to probe the existence of physics Beyond the Standard Model. A new run in 2007, aimed for a sub-percent precision measurement of $R_K$, has been proposed and approved. |
Physics Beyond the Standard Model |
|
cristina.lazzeroni@cern.ch |
| 156 |
CALICE Collaboration |
First CALICE SiW ECAL results from CERN and DESY test beams |
A prototype Silicon-Tungsten electromagnetic calorimeter for
an ILC detector was installed and tested during summer 2006
at DESY, and subsequently at the CERN SPS test beam.
The detector, consisted of about 6480 1x1 cm^2 silicon pads.
Data were collected with electron and hadron beams in the energy range
1 to 50 GeV. The analysis described focuses on the electromagnetic
shower reconstruction. This analysis is crucial to demonstrate the
quality of the calibration and detector understanding through
comparison with Monte Carlo simulations. In subsequent analysis,
the data will be combined with those recorded with the Calice analogue
HCAL in order to study hadronic showers with high spatial precision. |
Detectors and Data Handling |
|
David Ward |
| 157 |
The H1 and ZEUS Collaborations |
Combined results on charged current and neutral current
in deep inelastic scattering cross sections at HERA |
Measurements of the neutral current and charged current deep inelastic scattering cross sections at very high Q2 are performed by the H1 and ZEUS Collaborations.
The results from the full HERAI+II running period 1994-2007 of the two experiments are combined, corresponding to an integrated
luminosity of approximately 1 fb-1. The neutral current data provide measurements of the interference structure function xF_3^{gammaZ},
which is sensitive to the valence quark distributions at values of the Bjorken value x
as low as few 10^{-2}.
The polarized charged current results are used to set limits on right-handed charged current interactions.
The polarized cross section asymmetries in neutral current are used
to demonstrate parity violating effects in electroweak interactions.
Finally, from the dependence of the neutral current cross section on Q2, a combined limit on the quark charge radius is extracted.
|
Strong Interactions |
also submitted to the Electroweak and beyond the Standard Model session |
gallo@mail.desy.de |
| 158 |
The H1 and ZEUS Collaborations |
Combined results on charged current and neutral current
in deep inelastic scattering cross sections at HERA |
Measurements of the neutral current and charged current deep inelastic scattering cross sections at very high Q2 are performed by the H1 and ZEUS Collaborations.
The results from the full HERAI+II running period 1994-2007 of the two experiments are combined, corresponding to an integrated
luminosity of approximately 1 fb-1. The neutral current data provide measurements of the interference structure function xF_3^{gammaZ},
which is sensitive to the valence quark distributions at values of the Bjorken value x
as low as few 10^{-2}.
The polarized charged current results are used to set limits on right-handed charged current interactions.
The polarized cross section asymmetries in neutral current are used
to demonstrate parity violating effects in electroweak interactions.
Finally, from the dependence of the neutral current cross section on Q2, a combined limit on the quark charge radius is extracted.
|
High-Energy Electroweak Physics |
also submitted to the Strong Interactions and beyond the Standard Model session |
gallo@mail.desy.de |
| 159 |
NA48 collaboration |
Measurement of the CP violation parameter $|\eta_{+-}|$ and the charge asymmetry in $K^\pm \to 3\pi$ decays by NA48 and NA48/2 |
The main goal of the NA48 experiment at the CERN SPS has been the search for direct CP violation (CPV) in kaon decays. The observable $\eta_{+-}$ is related to the parameters of indirect and direct CPV ($\eta_{+-} = \varepsilon + \varepsilon^\prime$) and defined as the CP violating amplitude ratio of the neutral kaon decaying into two charged pions: $\eta_{+-} = A(K_L \to \pi^+\pi^-)/A(K_S \to \pi^+\pi^-)$. NA48 has determined $|\eta_{+-}|$ via the measurement of the ratio of decay rates $\Gamma(K_L \to \pi^+\pi^-)/\Gamma(K_L \to \pi e \nu)$. The data were taken during a dedicated run in 1999 using a pure $K_L$ beam. The analysis is based on 47000 $K_L \to \pi^+\pi^-$ and five million $K_L \to \pi e \nu$ decays. Complementary with $\varepsilon^\prime/\varepsilon$, the observable in the charged kaons sector is the asymmetry $A_g = (g^+ - g^-)/(g^+ + g^-)$ of the linear slope parameter $g$ in the Dalitz plot of $K^\pm \to 3\pi$ decays. Any non-zero value of $A_g$ would reflect evidence for direct CPV. SM predictions for the charge asymmetry give an upper limit of a few $10^{-5}$, while theoretical calculations involving processes beyond the SM do not exclude substantial enhancements of $A_g$. The NA48/2 experiment used simultaneous $K^+/K^-$ beams, and from the data samples taken in 2003 and 2004, $3.11 \times 10^9 K^\pm \to \pi^\pm\pi^+\pi^-$ and $9.13 \times 10^7 K^\pm \to \pi^\pm\pi^0\pi^0$ were selected. The charge asymmetry parameter $A_g$ was determined with a total uncertainty of $\sim 2\times 10^{-4}$ for each mode, ten times more accurate than previous measurements. |
Flavour Physics and CP Violation |
|
cristina.lazzeroni@cern.ch |
| 160 |
The H1 and ZEUS Collaborations |
Combined results on charged current and neutral current
in deep inelastic scattering cross sections at HERA |
Measurements of the neutral current and charged current deep inelastic scattering cross sections at very high Q2 are performed by the H1 and ZEUS Collaborations.
The results from the full HERAI+II running period 1994-2007 of the two experiments are combined, corresponding to an integrated
luminosity of approximately 1 fb-1. The neutral current data provide measurements of the interference structure function xF_3^{gammaZ},
which is sensitive to the valence quark distributions at values of the Bjorken value x
as low as few 10^{-2}.
The polarized charged current results are used to set limits on right-handed charged current interactions.
The polarized cross section asymmetries in neutral current are used
to demonstrate parity violating effects in electroweak interactions.
Finally, from the dependence of the neutral current cross section on Q2, a combined limit on the quark charge radius is extracted.
|
Physics Beyond the Standard Model |
also submitted to the Strong Interactions and the Electroweak sessions |
gallo@mail.desy.de |
| 161 |
NA48 collaboration |
Precision study of $K^\pm\to\pi^\pm\pi^0\pi^0$ and $K^\pm\to\pi^\pm\pi^+\pi^-$ Dalitz plot distibutions by NA48/2 |
The NA48/2 experiment at the CERN SPS has collected an unprecedented sample of 3-pion decays of charged kaons. The high statistics and the good resolution of the detectors allow a unique investigation of the detailed phase space distributions of these decays. The effects of final state pion rescattering observed in the Dalitz plot distribution of the $K^\pm\to\pi^\pm\pi^0\pi^0$ decays turned out to be a powerful tool for extraction of the S-wave pion-pion scattering lengths. The recent results obtained using a number of different theoretical approaches will be discussed, together with future prospects. The large statistics also allowed a precise measurement of the Dalitz plot slope parameters for the $K^\pm\to\pi^\pm\pi^+\pi^-$ decays, which will be discussed. |
Strong Interactions |
|
cristina.lazzeroni |
| 162 |
NA48 collaboration |
New precise measurements of radiative charged kaon decays |
The NA48/2-Experiment at the CERN SPS has recorded more than 2 billion charged kaon decays. From a sub-sample of this data set we have selected about 2 x 10^5 practically background free events of the decay K+- -> pi+- pi0 gamma, which is an order of magnitude more than from any previous experiment. The decay K+- -> pi+- pi0 gamma is dominated by Inner Bremsstrahlung (IB) of the K+- -> pi+- pi0 decay, but also exhibits a contribution of Direct Emission (DE), which is of high theoretical interest, as well as the interference between both amplitudes. We present a precise measurement of both the DE amplitude and the interference between IB and DE. In addition, using the full data set, we have made the first observation of the very rare decay K+- -> pi+- gamma e+ e-, which has large contributions from higher order pion loops. We have measured the branching fraction and the form factor of this decay. |
High-Energy Electroweak Physics |
Might also be included in Flavour Physics |
cristina.lazzeroni@cern.ch |
| 163 |
NA48 collaboration |
New precise results for Xi0 decays in NA48 |
We present new precise measurements of the lifetime of the neutral Xi0
hyperon and its radiative decays into the Lambda gamma and Sigma gamma
final states.
The data have been recorded with the NA48/1 experiment at the CERN SPS
from a total flux of more than 2 billion Xi0 decays. From this data set
we have improved significantly the knowledge on the Xi0 mean lifetime.
In addition, we analyzed a data sample of about 50000 Xi0 -> Lambda gamma
and 20000 Xi0 -> Sigma gamma decays, which exceeds present statistics by
about one order of magnitude.
We present new precise measurements of the decays asymmetries of these
decays, which play an important role in understanding the decay mechanism
of hyperon decays. |
High-Energy Electroweak Physics |
|
cristina.lazzeroni@cern.ch |
| 164 |
NA48 collaboration |
Precision study of $K^\pm\to\pi^\pm\pi^0\pi^0$ and $K^\pm\to\pi^\pm\pi^+\pi^-$ Dalitz plot distibutions by NA48/2 |
The NA48/2 experiment at the CERN SPS has collected an unprecedented sample of 3-pion decays of charged kaons. The high statistics and the good resolution of the detectors allow a unique investigation of the detailed phase space distributions of these decays. The effects of final state pion rescattering observed in the Dalitz plot distribution of the $K^\pm\to\pi^\pm\pi^0\pi^0$ decays turned out to be a powerful tool for extraction of the S-wave pion-pion scattering lengths. The recent results obtained using a number of different theoretical approaches will be discussed, together with future prospects. The large statistics also allowed a precise measurement of the Dalitz plot slope parameters for the $K^\pm\to\pi^\pm\pi^+\pi^-$ decays, which will be discussed. |
Strong Interactions |
|
cristina.lazzeroni@cern.ch |
| 165 |
NA48 collaboration |
The $K^+\rightarrow\pi^+\nu\bar{\nu}$ experiment at CERN |
The NA48/3-P326 proposal for an experiment to measure the branching
ratio of the very rare kaon decay $K^+\rightarrow\pi^+\nu\bar{\nu}$
at the CERN SPS will be described.
This will allow a 10% measurement of the CKM parameter |Vtd|.
The proposed experiment aims to
collect about 80 $K^+\rightarrow\pi^+\nu\bar{\nu}$ events with a
10\% of background in two years of data taking. The status of the
project, the R\&D and the future perspectives for the experiment
will be discussed. |
Flavour Physics and CP Violation |
might be also included in Electroweak session |
cristina.lazzeroni@cern.ch |
| 166 |
D. Barberis, K. Bos, M. Branco, D. Cameron, L. Goossens, A. Nairz, G. Poulard, P. Salgado |
ATLAS Computing System Commissioning: real-time data processing and distribution tests |
The ATLAS experiment is commissioning its computing system in preparation for LHC data. Part of this activity consists in testing the data flow from the online data acquisition to the offline processing system, and the distribution of raw and processed data to the external computing centres. A series of functional and rate tests has been performed in 2006 and 2007, allowing the optimisation of the hardware and software components of this system; the last phase of commissioning, the so-called Final Dress Rehearsal, consisting of an integration tests of all components, will take place later in 2007. This talk will describe the performed tests, the problems that we encountered, and the solutions we found. |
Detectors and Data Handling |
|
Dario.Barberis@cern.ch |
| 167 |
M. Ciuchini, E. Franco, G. Martinelli, M. Pierini, L. Silvestrini |
Dealing with hadronic uncertanties in charmless B decays: model independent approaches and charming penguins |
We discuss how, in spite of the presence of long distance contributions that invalidate
perturbative calculations in hadronic charmless
B decays, it is possible to extract interesting
information from the available experimental data.
We illustrate few cases i which penguin
contribution can be taken into account in a model-independent way, allowing to predict the
weak phases for channels which are differently
sensitive to new physics. We also how long distance contributions, such as charming
penguins model, can be obtained from data
even when a model-independent approach is not possible and how the Standard Model can be tested within this approach.
|
Flavour Physics and CP Violation |
|
maurizio.pierini@roma1.infn.it |
| 168 |
M. Bona, M. Ciuchini, E. Franco, V. Lubicz, G. Martinelli, F. Parodi, M. Pierini, P. Roudeau, C. Schiavi, L. Silvestrini, V. Sordini, A. Stocchi, V. Vagnoni |
Status of the Unitarity Triangle analysis in the Standard Model |
We present the update of the Unitarity Triangle
analysis in the Standard Model. Combining the
direct measurements on sides and angles of the
Unitarity Triangle, we determine the values of the CKM parameters rhobar and etabar. We discuss
the agreement of the current measurements and the
indirect determinations from the rest of the fit,
as well as the prediction on rare B and K decays.
This set of information provides the most poweful
test of the Standard Model from flavour physics |
Flavour Physics and CP Violation |
UTfit Collaboration |
maurizio.pierini@roma1.infn.it |
| 169 |
M. Bona, M. Ciuchini, E. Franco, V. Lubicz, G. Martinelli, F. Parodi, M. Pierini, P. Roudeau, C. Schiavi, L. Silvestrini, V. Sordini, A. Stocchi, V. Vagnoni |
The Unitarity Triangle analysis as a probe of New Physics |
Using the Unitarity Triangle analysis,
generalized to account for the presence of
physics behyond the Standard Model, we discuss
the current model-independent bounds on New
Physics contributions to K-Kbar, D-Dbar
and Bq-Bq bar (q=d,s) mixing processes. This
information is translated into a lower limit on
the probed scale of New Physics. We consider
several scenarios, such as New Physics with
generic flavour structure, NMFV, as well as MFV
with low, moderate or large values of tanbeta. |
Physics Beyond the Standard Model |
UTfit Collaboration |
maurizio.pierini@roma1.infn.it |
| 170 |
M. Bona, M. Ciuchini, E. Franco, V. Lubicz, G. Martinelli, F. Parodi, M. Pierini, P. Roudeau, C. Schiavi, L. Silvestrini, V. Sordini, A. Stocchi, V. Vagnoni |
The Unitarity Triangle analysis confronts Lattice QCD |
The overconstrained determinations of the angles
of the Unitarity Triangle allows to determine
the CKM parameters rhobar and etabar without
using inputs from lattice QCD. Using this
information and the experimental measurements of
K-Kbar and Bq-Bq bar (q=d,s) mixing processes,
as well as BR(B ->tau nu), we obtain a
data-driven determination of the lattice
parameters f_Bs, xi, B_K and Bhat, which allows
to test the predictions from non-perturbative
calculations. using this strategy, it is
possible to predict the value of Vub from the
determination of the CKM matrix and compare it
to the currently available inclusive and
exclusive determinations. |
Flavour Physics and CP Violation |
UTfit Collaboration |
maurizio.pierini@roma1.infn.it |
| 171 |
A. Donini, M. Maltoni, D. Meloni, P. Migliozzi and F. Terranova |
3+1 sterile neutrinos at the CNGS |
We study the potential of the CNGS beam in constraining the parameter space of a model with three active plus one sterile neutrino such as to explain the LSND results in case of a positive result of MiniBooNE. We perform our analysis using the OPERA detector as a reference.
We point out that the best channel to look for sterile neutrinos at the CNGS beam is $\nu_\mu \to \nu_\tau$, that is precisely the main signal for which OPERA has been built.
We also analyse $\nu_\mu \to \nu_e$ oscillations.
We take advantage of the expected efficiencies and backgrounds for these signals to make a realistic prediction of the potential of this experiment to look for sterile neutrinos.
Combination of data from both channels permit to cover almost all of the allowed CP-conserving 3+1 neutrino model parameter space.
|
Neutrino Physics |
|
meloni@roma1.infn.it |
| 172 |
Jaime Alvarez-Muniz and Pedro Facal for the Pierre Auger Collaboration |
Inclined showers at the Pierre Auger Observatory |
The cosmic ray showers detected at
the Pierre Auger Observatory and having
zenith angles greater than 60 degrees are the subject of a dedicated analysis. The spectrum of cosmic ray events above 10^19 eV and zenith angles between 60 and 80 degrees is presented and its implications discussed. The potential of the surface detector of the Pierre Auger Observatory for detecting neutrinos through deeply penetrating inclined showers having a significant electromagnetic component is studied, and an upper limit to the diffuse neutrino flux at EeV energies is presented. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
jaime@fpaxp1.usc.es |
| 173 |
H1 Collaboration |
D* Production in Deep-Inelastic Scattering with the H1 Detector |
Results on D* meson production in deep inelastic scattering at HERA are presented. The data were taken with the H1 detector in the years 2004 to 2006 and correspond to an integrated luminosity of 222 pb^-1. The analysis covers the kinematic region 5 < Q^2 < 100 GeV^2 and 0.051.5 GeV and |eta(D*)|<1.5 where
more than 10,000 $D*$ mesons are reconstructed. Single and double differential inclusive cross sections of D* meson production are
compared to LO predictions and a NLO calculation in the massive scheme. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 174 |
H1 Collaboration |
Study of the D* fragmentation function in deep-inelastic
ep scattering at HERA |
The charm fragmentation function
is studied using $D^{*\pm}$-meson
production close to the kinematic threshold in deep-inelastic scattering
as measured by the H1 detector at HERA. Two different methods are used for
the definition of the observable fraction $\rm{z}$ of the energy of the
$D^{*\pm}$-meson with respect to the charm quark. The energy of the charm
quark is approximated either by the energy of the jet including the
$D^{*\pm}$-meson or by the energy of a suitably defined hemisphere which
includes the $D^{*\pm}$-meson. The parameters of non-perturbative
fragmentation functions are extracted for two QCD models based on leading
order matrix elements and DGLAP or CCFM evolution of partons together with
string fragmentation and particle decays as well as for a next-to-leading
order QCD calculation in the fixed flavor scheme. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 175 |
H1 Collaboration |
Measurement of F_2^ccbar and F_2^bbbar using the H1
Vertex Detector at HERA
The inclusive charm and beauty cross sections are measured
in ep collisions at HERA in the kinematic region Q^2 > 6 GeV^2 |
The inclusive charm and beauty cross sections are measured
in ep collisions at HERA in the kinematic region Q^2 > 6 GeV^2 and
0.07
| Strong Interactions |
|
obehnke@mail.desy.de |
|
| 176 |
H1 Collaboration |
Measurement of Beauty Production in Deep-Inelastic Scattering
at HERA Using Events with Muons and Jets |
A measurement of the beauty production cross section in ep collisions at
a centre-of-mass energy of 319 GeV is presented. The data were collected
with the H1 detector at the HERA collider in the years 2005-2007 where an
integrated luminosity of approximately 276 pb^-1 were collected.
Events are selected by requiring the presence of jets and muons in the
final state. Both, the long lifetime and the large mass of b-flavoured
hadrons are exploited to identify events containing beauty quarks.
Differential cross sections are measured
in deep inelastic scattering, where 2 < Q^2 < 100 GeV^2.
The results are compared with perturbative
QCD calculations to leading and next-to-leading order. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 177 |
H1 Collaboration |
Measurement of Beauty Photo-Production at HERA Using Events with Muons and Jets |
A measurement of the beauty production cross section in ep collisions at
a centre-of-mass energy of 319 GeV is presented. The data were collected
with the H1 detector at the HERA collider in the years 2006-2007.
Events are selected by requiring the presence of jets and muons in the
final state. Both, the long lifetime and the large mass of b-flavoured
hadrons are exploited to identify events containing beauty quarks.
Differential cross sections are measured in photo-production (Q^2<1
GeV^2). The results are compared with perturbative
QCD calculations to leading and next-to-leading order. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 178 |
H1 Collaboration |
Measurement of Inelastic Electro-Production of J/Psi Mesons
in ep Scattering at HERA |
Inelastic electro-production of J/Psi mesons is studied in
$ep$-scattering at HERA. The data were taken with the H1 detector
in the years 2004 through 2006 and correspond to an integrated
luminosity of approximately 258 pb^-1. Single differential and double
differential cross sections and angular distributions are measured with
increased precision and purity compared to previous analyses. The
results are compared to theoretical predictions. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 179 |
H1 Collaboration |
Beam charge azimuthal asymmetry and deeply virtual compton scattering at
HERA II |
For the first time in a collider mode, an azimuthal cross section asymmetry
with respect to the charge of the incoming
lepton beam is reported from a study of exclusive electroproduction of real photons,
$e^{+,-} p \rightarrow e^{+,-} \photon p$ recorded with the H1 detector at HERA,
from the year 2003 till 2007. The analysed data sample corresponds to
an integrated luminosity of 300 pb$^{-1}$, equally shared in $e^+$ and $e^-$ incident lepton charge.
The observed asymmetry is attributed to the interference of the Bethe-Heitler and the
deeply virtual compton
scattering proceses.
It is observed in the kinematic domain
$6.5 < Q^2 < 80$~GeV$^2$ and $30 < W < 140$~GeV and
provides a direct access to
generalized parton distributions.
Using the complete data sample, elastic deeply virtual compton
scattering cross sections, $\gamma^* p \rightarrow \photon p$,
are measured, differentially in the square of the
invariant momentum transfer to the proton $t$, for different $Q^2$ and $W$ values.
The exponential $t$-slope parameters are then derived for different values
of $Q^2$ and $W$. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 180 |
H1 Collaboration |
Measurement and QCD interpretation of the diffractive cross section
at medium $Q^2$ |
Measurements of the cross section
for the diffractive process ep -> eXY
are presented in the kinematic region
$12 \leq Q^2 \leq 90$~GeV$^2$,
$0.01 \leq \beta \leq 0.90$ and $\xpom<0.1$, with
$M_{_Y} < 1.6 \ {\rm GeV}$ and $|t| < 1.0 \ {\rm GeV^2}$,
for an integrated luminosity of 120~pb$^{-1}$.
These data were recorded with the H1 detector during the years 1999, 2000 and 2005.
The diffractive events are selected requiring a large rapidity interval
between the hadronic systems $X$ and $Y$.
We also present a determination of the cross sections using a method
based on the different behaviour in $M_X$,
the invariant mass of the hadronic system $X$, of the diffractive and standard inclusive
contributions to the deep inelastic sample. Both approaches
are compared in the kinematic range of the analysis, showing a good agreement.
The diffractive structure function measurements are
analysed with a model based on the Regge phenomenology
and the $Q^2$ dependence of the Pomeron intercept is studied.
Measurements are then compared to a dipole model which
is found to give a very good description of the data
over the whole kinematic range. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 181 |
H1 Collaboration |
Measurement and QCD Analysis of the
Diffractive Deep-Inelastic Scattering Cross Section at HERA |
A detailed analysis is presented of the
diffractive deep-inelastic scattering process $ep\rightarrow eXY$, where
$Y$ is a proton or a low mass proton excitation carrying a fraction
$1 - \xpom > 0.95$ of the incident proton longitudinal momentum and
the squared four-momentum transfer at the proton vertex satisfies
$|t|<1 \ {\rm GeV^2}$. Using data taken by the H1 experiment,
the cross section is measured
for photon virtualities in the range
$3.5 \leq Q^2 \leq 1600 \rm\ GeV^2$,
triple differentially in $\xpom$, $Q^2$ and
$\beta = x / \xpom$, where $x$ is the Bjorken scaling variable.
At low $\xpom$,
the data are consistent with a factorisable
$\xpom$ dependence, which can be described by the exchange of an
effective pomeron trajectory with intercept
$\alphapom(0)= 1.118 \pm 0.008 \ {\rm (exp.)} \
^{+0.029}_{-0.010} \ {\rm (model)}$.
Diffractive parton distribution functions and their
uncertainties are determined
from a next-to-leading order DGLAP QCD analysis of the $Q^2$ and
$\beta$ dependences of the cross section. The
resulting gluon distribution carries
an integrated fraction of around $70 \%$ of the exchanged momentum
in the $Q^2$ range studied.
Total and differential cross sections are also measured
for the diffractive charged current process
$e^+ p \rightarrow \bar{\nu}_e XY$
and are found to be
well described by predictions based on the diffractive parton
distributions.
The ratio of the diffractive to the inclusive
neutral current $ep$ cross sections is studied.
Over most of the kinematic range, this ratio shows no significant
dependence on $Q^2$ at fixed $\xpom$ and $x$ or on $x$ at fixed
$Q^2$ and $\beta$.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 182 |
H1 Collaboration |
Diffractive Deep-Inelastic Scattering with a Leading Proton at HERA |
The cross section for the diffractive deep-inelastic scattering process $ep \to e X p$ is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data analysed cover the range \xpom <0.1 in fractional proton longitudinal momentum loss, 0.08 < |t| < 0.5 GeV^{-2} in squared four-momentum transfer at the proton vertex, 2 < Q^2 < 50 GeV^2 in photon virtuality and 0.004 < \beta = x / \xpom < 1, where x is the Bjorken scaling variable. For $\xpom \lapprox 10^{-2}$, the differential cross section has a dependence of approximately ${\rm d} \sigma / {\rm d} t \propto e^{6 t}$, independently of \xpom, \beta and Q^2 within uncertainties. The cross section is also measured triple differentially in \xpom, \beta and Q^2. The \xpom dependence is interpreted in terms of an effective pomeron trajectory with intercept $\alpha_{\pom}(0)=1.114 \pm 0.018 ({\rm stat.}) \pm 0.012 ({\rm syst.}) ^{+0.040}_{-0.020} ({\rm model})$ and a sub-leading exchange. The data are in good agreement with an H1 measurement for which the event selection is based on a large gap in the rapidity distribution of the final state hadrons, after accounting for proton dissociation contributions in the latter. Within uncertainties, the dependence of the cross section on x and Q^2 can thus be factorised from the dependences on all studied variables which characterise the proton vertex, for both the pomeron and the sub-leading exchange. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 183 |
H1 Collaboration |
Tests of QCD Factorisation in the Diffractive Production of Dijets in Deep-Inelastic Scattering and Photoproduction at HERA |
Measurements are presented of differential dijet cross sections in diffractive photoproduction (Q^2<0.01 GeV^2) and deep-inelastic scattering processes (DIS, 4 e X Y, in which the system X, containing at least two jets, is separated from a leading low-mass proton remnant system Y by a large rapidity gap. The dijet cross sections are compared with NLO QCD predictions based on diffractive parton densities previously obtained from a QCD analysis of inclusive diffractive DIS cross sections by H1. In DIS, the dijet data are well described, supporting the validity of QCD factorisation. The diffractive DIS dijet data are more sensitive to the diffractive gluon density at high fractional parton momentum than the measurements of inclusive diffractive DIS. In photoproduction, the predicted dijet cross section has to be multiplied by a factor of approximately 0.5 for both direct and resolved photon interactions to describe the measurements. The ratio of measured dijet cross section to NLO prediction in photoproduction is a factor 0.5+-0.1 smaller than the same ratio in DIS. This suppression is the first clear observation of QCD hard scattering factorisation breaking at HERA. The measurements are also compared to the two soft colour neutralisation models SCI and GAL. The SCI model describes diffractive dijet production in DIS but not in photoproduction. The GAL model fails in both kinematic regions. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 184 |
H1 Collaboration |
Diffractive Open Charm Production in Deep-Inelastic Scattering and Photoproduction at HERA |
Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep -> eX Y where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D*(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction. In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in diffractive DIS and photoproduction. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 185 |
H1 Collaboration |
Diffractive Photoproduction of Rho Mesons with Large Momentum Transfer at HERA |
The diffractive photoproduction of rho mesons, e p \to e rho Y, with large momentum transfer squared at the proton vertex, |t|, is studied with the H1 detector at HERA using an integrated luminosity of 20.1 pb^{-1}. The photon-proton centre of mass energy spans the range 75 < W < 95 GeV, the photon virtuality is restricted to Q^2 < 0.01 GeV^2 and the mass M_Y of the proton remnant is below 5 GeV. The t dependence of the cross section is measured for the range 1.5 < |t| < 10.0 GeV^2 and is well described by a power law, dsigma/ d|t| \propto |t|^{-n}. The spin density matrix elements, which provide information on the helicity structure of the interaction, are extracted using measurements of angular distributions of the rho decay products. The data indicate a violation of s-channel helicity conservation, with contributions from both single and double helicity-flip being observed. The results are compared to the predictions of perturbative QCD models. |
Strong Interactions |
hep-ex/0603038 |
obehnke@mail.desy.de |
| 186 |
H1 Collaboration |
Elastic J/Psi Production at HERA |
Cross sections for elastic production of J/Psi mesons in photoproduction and electroproduction are measured in electron proton collisions at HERA using an integrated luminosity of 55 pb^{-1}. Results are presented for photon virtualities Q^2 up to 80 GeV^2. The dependence on the photon-proton centre of mass energy W_{gamma p} is analysed in the range 40 < \Wgp < 305 GeV in photoproduction and 40 < \Wgp < 160 GeV in electroproduction. The \Wgp dependences of the cross sections do not change significantly with Q^2 and can be described by models based on perturbative QCD. Within such models, the data show a high sensitivity to the gluon density of the proton in the domain of low Bjorken x and low Q^2. Differential cross sections d\sigma/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range |t|<1.2 GeV^2 as functions of \Wgp and Q^2. Effective Pomeron trajectories are determined for photoproduction and electroproduction. The J/Psi production and decay angular distributions are consistent with s-channel helicity conservation. The ratio of the cross sections for longitudinally and transversely polarised photons is measured as a function of Q^2 and is found to be described by perturbative QCD based models. |
Strong Interactions |
hep-ex/0510016 |
obehnke@mail.desy.de |
| 187 |
H1 Coillaboration |
Forward Jet Production in Deep Inelastic Scattering at HERA |
The production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable (x_{Bj}) and as triple differential cross sections d^3 \sigma / dx_{Bj} dQ^2 dp_{t,jet}^2, where Q^2 is the four momentum transfer squared and p_{t,jet}^2 is the squared transverse momentum of the forward jet. Also cross sections for events with a di-jet system in addition to the forward jet are measured as a function of the rapidity separation between the forward jet and the two additional jets. The measurements are compared with next-to-leading order QCD calculations and with the predictions of various QCD-based models. |
Strong Interactions |
hep-ex/0508055 |
obehnke@mail.desy.de |
| 188 |
H1 Collaboration |
Photoproduction of Dijets with High Transverse Momenta at HERA |
Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q^2 < 1 GeV^2 with the H1 detector at the HERA ep collider using an integrated luminosity of 66.6 pb^{-1}. Jets are defined with the inclusive k_T algorithm and a minimum transverse momentum of the leading jet of 25 GeV is required. Dijet cross sections are measured in direct and resolved photon enhanced regions separately. Longitudinal proton momentum fractions up to 0.7 are reached. The data compare well with predictions from Monte Carlo event generators based on leading order QCD and parton showers and with next-to-leading order QCD calculations corrected for hadronisation effects. |
Strong Interactions |
hep-ex/0603014 |
obehnke@mail.desy.de |
| 189 |
H1 Collaboration |
Measurement of Charm and Beauty Dijet Cross Sections in Photoproduction at HERA using the H1 Vertex Detector |
A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum $p_t^{jet}_{1(2)}>11(8)$ GeV in the central range of pseudo-rapidity $-0.9<\eta^{jet}_{1(2)}<1.3$. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable $x_{\gamma}^{obs}$. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement. |
Strong Interactions |
hep-ex/0605016 |
obehnke@mail.desy.de |
| 190 |
H1 Collaboration |
Search for a Narrow Baryonic Resonance Decaying to $K^0_s p$ or $K^0_s \barp$ in Deep Inelastic Scattering at HERA |
A search for a narrow baryonic resonance decaying to $K^0_s p$ or $K^0_s \bar p$ is carried out in deep inelastic ep scattering with the H1 detector at HERA. Such a resonance could be a strange pentaquark \thplns, evidence for which has been reported by several experiments. The $K^0_s p$ and $K^0_s \bar p$ invariant mass distributions presented here do not show any significant peak in the mass range from threshold up to 1.7 GeV. Mass dependent upper limits on $\sigma(ep \to e \thplf X)\times BR(\thplf \to K^0 p)$ are obtained at the 95% confidence level. |
Strong Interactions |
hep-ex/0604056 |
obehnke@mail.desy.de |
| 191 |
H1 Collaboration |
Inclusive D* Meson Cross Sections and D* Jet Correlations in Photoproduction at HERA |
Differential photoproduction cross sections are measured for events containing D* mesons. The data were taken with the H1 detector at the ep collider HERA and correspond to an integrated luminosity of 51.1 pb-1. The kinematic region covers small photon virtualities Q^2 < 0.01 GeV^2 and photon-proton centre-of-mass energies of 171 < W_gammap < 256 GeV. The details of the heavy quark production process are further investigated in events with one or two jets in addition to the D* meson. Differential cross sections for D* jet production are determined and the correlations between the D* meson and the jet(s) are studied. The results are compared with perturbative QCD predictions applying collinear- or kt -factorisation. |
Strong Interactions |
hep-ex/0608042 |
obehnke@mail.desy.de |
| 192 |
H1 Collaboration |
Production of D* Mesons with Dijets in Deep-Inelastic Scattering at HERA |
Inclusive D* production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D* meson is investigated. The analysis covers values of photon virtuality 2< Q^2 <=100 GeV^2 and of inelasticity 0.05<= y <= 0.7. Differential cross sections are measured as a function of Q^2 and x and of various D* meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon-gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the k_T-unintegrated gluon distribution of the proton. |
Strong Interactions |
hep-ex/0701023 |
obehnke@mail.desy.de |
| 193 |
H1 Collaboration |
Tau Lepton Production in ep Collisions at HERA |
The production of tau leptons in ep collisions is investigated using
data recorded by the H1 detector at HERA in the period 1994-2000. Tau
leptons are identified by detecting their decay products, using
leptonic and hadronic decay modes. The cross section for the
production of tau lepton pairs is measured for the first time at
HERA. Furthermore, a search for events with an energetic isolated tau
lepton and with large missing transverse momentum is performed. The
results are found to be in agreement with the Standard Model
predictions. |
Physics Beyond the Standard Model |
hep-ex/0604022 |
obehnke@mail.desy.de |
| 194 |
H1 Collaboration |
Search for Lepton Flavour Violation in ep Collisions at HERA |
A search for the lepton flavour violating processes ep~$\rightarrow
\mu$~X and ep$\rightarrow \tau$~X is performed with the H1 experiment
at HERA. Final states with a muon or tau and a hadronic jet are
searched for in a data sample corresponding to an integrated
luminosity of 66.5~pb$^{-1}$ for $e^{+}p$ collisions and
13.7~pb$^{-1}$ for $e^{-}p$ collisions at a centre-of-mass energy of
319~GeV. No evidence for lepton flavour violation is found. Limits are
derived on the mass and the couplings of leptoquarks inducing lepton
flavour violation in an extension of the
Buchm\"{u}ller-R\"{u}ckl-Wyler effective model. Leptoquarks produced
in ep collisions with a coupling strength of $\lambda$=0.3 and
decaying with the same coupling strength to a muon-quark pair or a
tau-quark pair are excluded at 95\% confidence level up to masses of
459~GeV and 379~GeV, respectively. |
Physics Beyond the Standard Model |
hep-ex/0703004 |
obehnke@mail.desy.de |
| 195 |
H1 Collaboration |
Search for Doubly-Charged Higgs Boson Production at HERA |
A search for the single production of doubly-charged Higgs bosons
$H^{\pm \pm}$ in ep collisions is presented. The signal is searched
for via the Higgs decays into a high mass pair of same charge leptons,
one of them being an electron. The analysis uses up to 118~pb$^{-1}$
of $e^{\pm}p$ data collected by the H1 experiment at HERA. No evidence
for doubly-charged Higgs production is observed and mass dependent
upper limits are derived on the Yukawa couplings $h_{el}$ of the Higgs
boson to an electron-lepton pair. Assuming that the doubly-charged
Higgs only decays into an electron and a muon via a coupling of
electromagnetic strength $h_{e \mu} = \sqrt{4 \pi \alpha_{em}}$=0.3, a
lower limit of 141~GeV on the $H^{\pm\pm}$ mass is obtained at the
95\% confidence level. For a doubly-charged Higgs decaying only into
an electron and a tau and a coupling $h_{e\tau}$=0.3, masses below
112~GeV are ruled out. |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 196 |
H1 and ZEUS Collaborations |
Measurement of Events with Isolated Leptons and Missing Pt at HERA |
A search for events containing isolated high transverse energy
electrons or muons and large missing transverse momentum produced in
$e^{\pm}p$ collisions is performed with the H1 and ZEUS detectors at
HERA using data taken in the period 1994-2007. The measurements are
performed by H1 and ZEUS in a common phase space and combined in an
analysis corresponding to a total integrated luminosity of
1~fb$^{-1}$. The results are compared to the Standard Model
prediction, in particular for events containing in addition a
prominent hadronic jet, where an excess was previously reported by the
H1 collaboration. The cross section for the single production of $W$
bosons at HERA is also presented. |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 197 |
H1 Collaboration |
Search for Multi-Lepton Events at HERA |
A search for for multi-lepton (electron or muon) events at high
transverse momenta in ep-collisions with the H1 detector at HERA is
presented, using the complete H1 dataset taken in the years 1994-2007,
corresponding to an integrated luminosity of 471~pb$^{-1}$. With
respect to the published HERA I multi-electron and multi-muon
analyses, additional topologies with high $P_T$ electrons and muons
are investigated. Yields of di-lepton and tri-lepton events are
measured and a general good agreement is found with the Standard Model
(SM) predictions |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 198 |
H1 and ZEUS Collaborations |
Search for Multi-Lepton Events at HERA |
A search for multi-lepton (electron or muon) events at high transverse
momenta is performed by the H1 and ZEUS Collaborations. The
measurements are performed by H1 and ZEUS in a common phase space and
combined in an analysis corresponding to a total integrated luminosity
of 1~fb$^{-1}$. The results are compared to the Standard Model
prediction |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 199 |
H1 Collaboration |
Generic Analysis on HERA II Data |
A model-independent search for deviations from the Standard Model
prediction is performed using e$^{\pm}$p data collected in 2003-07 by
the H1 experiment at HERA. All event topologies involving isolated
electrons, photons, muons, neutrinos and jets with high transverse
momenta are investigated in a single analysis. Events are assigned to
exclusive classes according to their final state. A statistical
algorithm is applied to search for deviations from the Standard Model
in the distributions of the scalar sum of transverse momenta or
invariant mass of final state particles and to quantify their
significance. |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 200 |
H1 Collaboration |
Search for Excited Neutrinos at HERA |
A search for excited neutrinos is performed using $e^{-}p$ data
collected in the years 1998-99 and 2005-06 by the H1 experiment at
HERA at center-of-mass energy of 318 GeV, with a coresponding
integrated luminosity of 184~pb$^{-1}$. The electroweak decays of
excited neutrinos, $\nu^{*}~\rightarrow~\nu~\gamma$,
$\nu^{*}~\rightarrow~\nu~Z$, $\nu^{*}~\rightarrow~eW$ are considered
and possible final states resulting from the Z or W hadronic and
leptonic decays are taken into account. No evidence for excited
neutrino production is found. Mass dependent exclusion limits are
determined for the ratio of the coupling to the compositeness scale,
f/L. These limits extend the excluded region to higher masses than has
been possible in previous searches. |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 201 |
H1 Collaboration |
Search for Excited Electrons at HERA |
A search for excited electrons is performed using $e^{\pm}p$ data
collected in the years 1998-2000 and 2003-07 by the H1 experiment at
HERA at center-of-mass energy of 318 GeV. The electroweak decays of
excited electrons, $e^{*}~\rightarrow~e~\gamma$,
$e^{*}~\rightarrow~eZ$, $e^{*}~\rightarrow~\nu~W$ are considered and
possible final states resulting from the Z or W hadronic decays are
taken into account. No evidence for excited electron production is
found. Mass dependent exclusion limits are determined for the ratio of
the coupling to the compositeness scale, f/L. These limits extend the
excluded region to higher masses than has been possible in previous
searches |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 202 |
H1 Collaboration |
Search for Excited Quarks at HERA |
A search for excited quarks is performed using $e^{\pm}p$ data
collected in the years 1999-2000 and 2003-07 by the H1 experiment at
HERA at center-of-mass energy of 318 GeV. The electroweak decays of
excited electrons, $q^{*}~\rightarrow~q~\gamma$,
$q^{*}~\rightarrow~qZ$, $q^{*}~\rightarrow~qW$ are considered and
possible final states resulting from the Z or W decays are taken into
account |
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 203 |
H1 Collaboration |
Search for Leptoquarks in $e^{\pm}p$ Collisions at HERA |
A search for scalar and vector leptoquarks coupling to first
generation fermions performed in the H1 experiment using $e^{\pm}p$
data collected in the years 2003-2007 is presented. Especially the
sensitivity to leptoquarks with fermion number F=2 is increased
substantially w.r.t. the previous H1 results. No significant evidence
for the direct production of such particles is found in a data sample
with a large transverse momentum final state electron or with large
missing transverse momentum. The results of the present analysis are
thus combined with those of the searches in the e+p and e-p data of
the HERA I phase in order to set new constraints on leptoquark models.
|
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 204 |
H1 Collaboration |
Measurement of Event Shape Variables in Deep-Inelastic Scattering at HERA |
Deep-inelastic ep scattering data taken with the H1 detector at HERA and corresponding to an integrated luminosity of 106 pb^{-1} are used to study the differential distributions of event shape variables. These include thrust, jet broadening, jet mass and the C-parameter. The four-momentum transfer Q is taken to be the relevant energy scale and ranges between 14 GeV and 200 GeV. The event shape distributions are compared with perturbative QCD predictions, which include resummed contributions and analytical power law corrections, the latter accounting for non-perturbative hadronisation effects. The data clearly exhibit the running of the strong coupling alpha_s(Q) and are consistent with a universal power correction parameter alpha_0 for all event shape variables. A combined QCD fit using all event shape variables yields alpha_s(mZ) = 0.1198 \pm 0.0013 ^{+0.0056}_{-0.0043} and alpha_0 = 0.476 \pm 0.008 ^{+0.018} _{-0.059}. |
Strong Interactions |
hep-ex/0512014 |
obehnke@mail.desy.de |
| 205 |
H1 Collaboration |
Inclusive Jet Production in Deep-Inelastic Scattering at High $Q^2$ at HERA and determination of the strong coupling |
Inclusive jet production is studied in neutral
current deep-inelastic positron-proton scattering at large
four momentum transfer squared $Q^2>150\gev^2$ with the H1
detector at HERA. The data were collected with
the H1 detector at HERA in the years 1999 to 2000.
Single and double differential inclusive jet cross sections are measured
as a function of the four-momentum transfer squared $Q^2$ and of the transverse energy
$E_T$ of the jets in the Breit frame.
The jet cross sections are found to be well described by
calculations at next-to-leading order perturbative QCD.
The running of the strong coupling constant is demonstrated
and the value of $\alpha_s(M_Z)$ is determined.
The ratio of the inclusive jet cross section to the inclusive neutral
current cross section is also measured and it yields an even more precise
value for $\alpha_s(M_Z)$.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 206 |
H1 Collaboration |
A New Measurement of Exclusive rho^0 Meson Photoproduction |
Using a sample of more than 240000 events taken with the H1 detector
at HERA in 2005, a new measurement of exclusive
$\rho^0$ photoproduction in the kinematic range $20 < W < 90\,\GeV$
and $|t| < 3\,\GeV^2$ is performed.
From the measurement of
the $W$ dependence of this process in eight bins of $t$,
the Pomeron trajectory $\alpha\sub{\pom}\,(t)$ can be extracted
for the first time from the data of a single experiment.
The result is $\alpha\sub{\pom}\,(t)$ =
1.093 \pm 0.003 (stat.) ^{+0.008}_{-0.007} +
[ 0.116 \pm 0.027 (stat.) ^{+0.036}_{-0.046} (syst.)} ,\GeV^{-2} ] \cdot t
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 207 |
H1 Collaboration |
Search for Baryonic Resonances Decaying to Xi pi in Deep-Inelastic Scattering at HERA } |
A search for narrow baryonic resonances decaying into
Xi- pi- or Xi- pi+ and their antiparticles
is carried out
with the H1 detector using deep inelastic scattering events at HERA
in the range of negative photon four-momentum transfer squared
2 < Q2 < 100 GeV^2.
No signal is observed for a new baryonic state in
the mass range $1600 - 2300 \mev$
in either the doubly charged
or the neutral decay channels.
The known baryon Xi(1530)^0 is observed through its
decay mode into Xi-pi+.
Upper limits are given on the ratio of the production rates
of new baryonic states, such as the hypothetical pentaquark states Xi^{--}_{5q} or Xi^{0}_{5q}
relative to the \xizero baryon state.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 208 |
D.F. Cowen for The IceCube Collaboration |
Neutrino Physics with IceCube |
The IceCube neutrino detector at the South Pole is presently the world's largest, instrumenting a volume of roughly 0.25 cubic kilometers. It surrounds the existing AMANDA detector, forming a more densely pixelated inner core region. Operated in coincidence, these detectors are in principle sensitive to neutrinos with energies ranging from below 100 GeV to above 1 EeV. Over this range, we will be able to explore the fundamental properties of neutrinos from atmospheric and presumed cosmological sources, indirectly search for WIMP dark matter, and directly search for monopoles and other exotica. IceCube is designed to map the neutrino sky in an unexplored region spanning over five orders of magnitude in energy, and will be sensitive to cosmological neutrinos of all flavors from sources such as Gamma Ray Bursts and Active Galactic Nuclei.
Recent results from IceCube, the current status of the IceCube detector, and future plans will be presented. |
Neutrino Physics |
|
cowen@phys.psu.edu |
| 209 |
B. El-Bennich, O. Leitner, J.-P. Dedonder and B. Loiseau |
Pseudoscalar-scalar transition form factors in $D$ decays |
Decay amplitudes of $D(D_s) \to S-PS$, where $S$ and $PS$ mean scalar and pseudoscalar mesons respectively, are
compared to experimental branching ratios (mainly provided by the Babar and Belle facilities) in order to predict $D(D_s) \to S$ transition form factors in these amplitudes. Testing QCD factorization for $D$ decays involving scalar mesons, we focus on the cases where $S=f_0(600), \kappa, f_0(980), a_0(980), K_0^{0*}, K_0^*(1430)$ and where $PS=\pi$ or $K$.
We can take advantage of these reactions to efficiently constrain the transition form factors obtained in two different relativistic quark models, i.e. the dispersion relation approach and the covariant light front formalism. Working within the constituent quark model, we phenomenologically determine the wave functions for the scalars involved in $D(D_s) \to S-PS$. The work presented here is a generalization of our previous
calculations for $S=f_0(980)$. Anticipating the upcoming
experimental data from CLEO-c, we hope to be getting more constraints in our analysis. Finally, predictions for $B \to S$ transition form factors will be also shown as an extension of our model. |
Flavour Physics and CP Violation |
|
lbennich@lpnhe.in2p3.fr |
| 210 |
Hai-Yang Cheng, Chun-Khiang Chua, Amarjit Soni |
Charmless Three-body Decays of B Mesons |
Charmless 3-body decays of B mesons are studied in the framework of the factorization approach. The 3-body decay process consists of resonant
contributions and the nonresonant signal. The
intermediate vector meson contributions to 3-body decays are identified through the vector current, while the scalar meson resonances are mainly associated with the scalar density. Their
effects are described in terms of the Breit-Wigner formalism. Apart from the nonresonant contributions arising from B to P_1P_2 transitions we have identified another large source of the nonresonant signal in the matrix elements of scalar densities. We have computed resonant and nonresonant contributions
to charmless 3-body decays and studied their direct CP and mixing-indcued CP asymmetries. |
Flavour Physics and CP Violation |
|
phcheng@phys.sinica.edu.tw |
| 211 |
Adam Trzupek, for the PHOBOS Collaboration |
Results from the PHOBOS experiment at RHIC |
Recent results from the PHOBOS experiment will be reviewed. Scaling properties of global characteristics of Cu+Cu and Au+Au collisions at RHIC energies, including charged particle multiplicity and elliptic flow, will be presented. Results on charged particle transverse momentum spectra as a function of collision energy and system size will also be presented.
|
High-Energy Nuclear Physics |
|
Adam.Trzupek@ifj.edu.pl |
| 212 |
hai-Yang Cheng, Chun-Khiang Chua, Kwei-Chou Yang |
Charmless hadronic B decays involving scalar mesons |
The hadronic charmless B decays into a scalar meson and a pseudoscalar meson or a vector meson are investigated within the framework of QCD factorization. The experimental measurements of these decays will provide valuable information on the nature of the even-parity mesons. For example, we point out that the predicted B^0 to a_0(980)^+\pi^- and a_0^+(980)K^- rates exceed the current experimental limits, favoring a four-quark nature for the
a_0(980). The decay of B to \kappa^+ K^- also provides a nice ground for testing the 4-quark and 2-quark nature of the \kappa meson. It can proceed through W-exchange and hence is quite suppressed if \kappa is made of two quarks, while it receives a tree contribution if \kappa is predominately a four-quark state. |
Flavour Physics and CP Violation |
|
phcheng@phys.sinica.edu.tw |
| 213 |
Hai-Yang Cheng, Chun-Khiang Chua |
Spectroscopy and Strong Decays of Charmed Baryons |
Many new excited charmed baryon states have been
discovered by BaBar, Belle and CLEO in recent years. Charmed baryon spectroscopy provides an ideal place for studying the dynamics of the light quarks in the environment of a heavy quark. We analyze the strong decays of charmed baryons in the framework of heavy hadron chiral perturbation theory. We also discuss the first positive-parity excited charmed baryons and make a conjecture on the states \Lambda_c(2880), Lambda_c(2940), \Xi_c(2980) and \Xi_c(3077). |
Strong Interactions |
|
phcheng@phys.sinica.edu.tw |
| 214 |
Peter Krizan (for the Belle Aerogel RICH group) |
Proximity focusing RICH with TOF capabilities |
A proximity focusing RICH with aerogel radiator has been studied to further improve the pion-kaon separation in the forward region of the Belle
spectrometer. Such a proximity focusing RICH counter is also a very fast detector, in particular if a micro-channel plate (MCP) PMT is used as the photon detector. With its excellent timing properties, the same device could
also serve as a time-of-flight counter and thus supplement other identification methods, in particular for low momentum tracks. Cherenkov
photons emitted in the radiator medium (aerogel) as well as in the entrance window of the PMT could be used for the time-of-flight measurement. A prototype of this novel device using BURLE 85011 64-anode, microchannel plate PMT, was tested on the bench and in the test beam at KEK. Excellent performance of this counter could be demonstrated. In particular, a good separation of pions and protons was observed in the test beam data with a time-of-flight resolution of about 35ps (rms) for Cherenkov photons produced in the PMT window.
|
Detectors and Data Handling |
|
peter.krizan@ijs.si |
| 215 |
S. Descotes-Genon, J. Matias, J. Virto |
Connecting B_d and B_s decays with flavour symmetries and QCD factorisation |
We present an analysis of penguin-dominated B_d and B_s decay modes within the SM, relating them in a controlled way through SU(3)-flavour symmetry and QCD-improved factorisation. We propose a set of sum rules for the observables related to such decays. To illustrate our purpose, we determine observables for some B_s decays, such as B_s->K0K0, as functions of their B_d counterpart, and discuss the phenomenological impact of such relations. |
Flavour Physics and CP Violation |
"hep-ph/0701116, hep-ph/0611280, hep-ph/0603239" |
descotes@th.u-psud.fr |
| 216 |
S. Descotes-Genon |
Pi-pi and pi-K scatterings in resummed Chiral Perturbation Theory |
Chiral symmetry breaking may exhibit significantly different patterns in two chiral limits: N_f=2 massless flavours (m_u=m_d=0, m_s physical) and N_f=3 massless flavours (m_u=m_d=0=m_s=0). Such a difference, related to the violation of the Zweig rule in the scalar sector, could yield a numerical competition between contributions counted as leading order and next-to-leading in the chiral expansions of observables. We introduce Resummed Chiral Perturbation Theory to deal with such instabilities. We analyse data on pi-pi and pi-K scatterings within this framework to constrain the quark mass ratio as well as the quark condensate and the pseudoscalar decay constant in the N_f=3 chiral limit. The results favour significant contributions of vacuum fluctuations suppressing the N_f=3 quark condensate compared to its N_f=2 counterpart. |
Strong Interactions |
hep-ph/0703154 |
descotes@th.u-psud.fr |
| 217 |
Rok Pestotnik |
Silicon photomultiplier as a position sensitive detector of Cherenkov photons |
Silicon photomultipliers are semiconductor photo-sensitive devices build from an avalanche photodiode (APD) matrix on a common silicon substrate, working in the limited Geiger mode. One of the benefits if compared to other position sensitive detectors which are used in the Ring
Imaging Cherenkov (RICH) Counters is their insensitivity to the high magnetic fields. They have several other advantages (lower operation voltage, less material) over the conventional photomultiplier tubes. They also have a high peak photon detection efficiency (approx 20%), a high gain of ~10^6 and a good time response. Due to their dimensions, they allow compact, light and robust mechanical designs. All this would make them a very promising candidate for a photon detector of Cherenkov photons in a RICH counter. However, due to their serious disadvantage, a very high dark rate (~1 MHz), they have up to now never been used in Cherenkov detectors, where single photon detection is required at low noise.
One of the main issues of the present study was therefore to adapt this photo-sensor to single photon counting. In the contribution we will present the experimental results on the measurements of single photo-electron pulse height and timing distribution, uniformity of the response and photon detection efficiency of individual SiPMs.
From an array of SiPMs a small prototype detector has been constructed and tested with Cherenkov photons from cosmic muons. To increase the efficiency of such a detector, different light collection systems have been evaluated.
At the end we will discuss the design optimization of a proximity focusing RICH counter for the upgraded Belle spectrometer with silica aerogel as the radiator medium and the SiPM array as the photon detector.
|
Detectors and Data Handling |
|
rok.pestotnik@ijs.si |
| 218 |
S. Descotes-Genon and B. Moussallam |
The kappa meson from Roy-Steiner representations of pi-K scattering |
We discuss the existence of the light scalar meson K^*_0(800) (also called kappa) in a rigorous way, by showing the presence of a pole in the pi K --> pi K amplitude on the second Riemann sheet. For this purpose, we study the domain of validity of two classes of Roy-Steiner representations in the complex energy plane. We prove that one of them is valid in a region sufficiently broad in the imaginary direction. From this representation, we compute the l=0 partial wave in the complex plane with neither additional approximation nor model dependence, relying only on experimental data. A scalar resonance with strangeness S=1 is found with the following mass and width: E_kappa = 658 \pm 13 MeV and Gamma_kappa = 557 \pm 24 MeV. |
Strong Interactions |
"hep-ph/0607133, hep-ph/0310283 " |
descotes@th.u-psud.fr |
| 219 |
V.I.Kolesnikov, G.L.Melkumov for the NA49 Collaboration |
Anti-nuclei and Nuclei Production in Pb+Pb Collisions at CERN SPS Energies. |
Results of a comprehensive study of light (anti)nuclei production in Pb+Pb collisions at SPS energies (20A, 30A, 40A, 80A and 158A GeV) carried out by the NA49 experiment at the CERN SPS will be reported. Rapidity and transverse momentum spectra of helium (A=3), tritium, deuteron and anti-deuteron as well as protons and anti-protons were measured. Broad phase-space coverage allow to obtain for the first time total multiplicity of helium (A=3) and its dependence on incident energy and collision centrality in the entire SPS energy domain. A surprisingly good agreement is observed between the measured yields for helium and those predicted by the Statistical Hadronization Model. The mid-rapidity transverse mass spectra of tritium, deuteron, ant-deuteron, proton and anti-proton were measured in centrality selected Pb+Pb collisions at 20A-158A GeV. The dependence of the yield ratios and the inverse slope parameter of the m_T spectra on collision energy, centrality and the mass number of the produced nucleus will be presented and discussed within coalescence and statistical approaches. |
High-Energy Nuclear Physics |
|
kolesnik@moonhe.jinr.ru |
| 220 |
FP420 Collaboration |
The FP420 project: the challenge of measuring forward protons at the LHC |
FP420 is an R&D project to assess the feasibility of installing proton
detectors at 420m from the ATLAS and CMS interaction points at the LHC.
They would function as new sub-detectors at ATLAS/CMS, allowing the
measurement of the spatial position and arrival time of protons scattered
at very low angles with fractional momentum loss between 0.2% and 2%.
Forward proton tagging in this region is expected to open a new programme
of electroweak, QCD and BSM physics. The challenges of the project are
presented, along with the solutions envisaged, notably for the replacement
cryostat, the detectors, the moving mechanism to bring the detectors close
to the beam, and the alignment.
|
Detectors and Data Handling |
|
arneodo@to.infn.it |
| 221 |
FP420 Collaboration |
The FP420 project: the physics potential |
FP420 is an R&D project to assess the feasibility of installing proton
detectors at 420m from the ATLAS and CMS interaction points at the LHC.
They would function as new sub-detectors at ATLAS/CMS, allowing the
measurement of the spatial position and arrival time of protons scattered
at very low angles with fractional momentum loss between 0.2% and 2%. Such
detectors would allow the possibility of exploiting the central exclusive
production process to extend the discovery reach of ATLAS and CMS. The
physics program of FP420 is discussed, including central exclusive
production of light Standard Model or MSSM Higgs Bosons, the measurement
of the Higgs quantum numbers, and a wide range of electroweak, QCD and BSM
physics.
|
Strong Interactions |
"Also submitted to the following Sessions: High-Energy Electroweak Physics, Physics Beyond the Standard Model" |
arneodo@to.infn.it |
| 222 |
FP420 Collaboration |
The FP420 project: the physics potential |
FP420 is an R&D project to assess the feasibility of installing proton
detectors at 420m from the ATLAS and CMS interaction points at the LHC.
They would function as new sub-detectors at ATLAS/CMS, allowing the
measurement of the spatial position and arrival time of protons scattered
at very low angles with fractional momentum loss between 0.2% and 2%. Such
detectors would allow the possibility of exploiting the central exclusive
production process to extend the discovery reach of ATLAS and CMS. The
physics program of FP420 is discussed, including central exclusive
production of light Standard Model or MSSM Higgs Bosons, the measurement
of the Higgs quantum numbers, and a wide range of electroweak, QCD and BSM
physics.
|
High-Energy Electroweak Physics |
"Also submitted to the following Sessions: Strong Interactions, Physics Beyond the Standard Model" |
arneodo@to.infn.it |
| 223 |
FP420 Collaboration |
The FP420 project: the physics potential |
FP420 is an R&D project to assess the feasibility of installing proton
detectors at 420m from the ATLAS and CMS interaction points at the LHC.
They would function as new sub-detectors at ATLAS/CMS, allowing the
measurement of the spatial position and arrival time of protons scattered
at very low angles with fractional momentum loss between 0.2% and 2%. Such
detectors would allow the possibility of exploiting the central exclusive
production process to extend the discovery reach of ATLAS and CMS. The
physics program of FP420 is discussed, including central exclusive
production of light Standard Model or MSSM Higgs Bosons, the measurement
of the Higgs quantum numbers, and a wide range of electroweak, QCD and BSM
physics.
|
Physics Beyond the Standard Model |
"Also submitted to the following Sessions: Strong Interactions, High-Energy Electroweak Physics" |
arneodo@to.infn.it |
| 225 |
E.N. Myasnikov, E.V. Mastropas |
Spontaneous breaking of spatial homogeneity of vacuum by quarks and properties of hadrons. |
A possible breaking of spatial homogeneity of vacuum due to the interaction between quark and Bose-field is analyzed. It is shown that in this case quark can be in a localized state (like wave packet). Energetic conditions for such a spontaneous symmetry breaking are found in suggested model. Possible consequences of such symmetry breaking, in particular, the origin of deep inelastic processes and quark confinement phenomenon are discussed.
|
Flavour Physics and CP Violation |
|
mastropas@rambler.ru |
| 226 |
U. Jamil and J. K. Sarma |
Solutions of Polarized Coupled DGLAP Evolution Equations for Singlet and Gluon Structure Functions in Next to Leading Order at low-x |
In this paper, we solved the polarized coupled Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations for singlet and gluon structure functions in next to leading order (LO) at low-x assuming the Regge behaviour of polarized quark and gluon structure functions at this limit, and t and x-evolutions of polarized singlet and gluon structure functions are presented. We have compared our theoretical work with SLAC-E-143, SLAC-E-154, SMC collaborations data and also with the curve obtained solving unified evolution equation by numerical method. We have shown that the solutions of polarized coupled equations give accurate results for the polarized structure functions and also the compatibility of Regge behaviour of polarized quark and gluon structure functions with perturbative quantum chromodynamics (PQCD) at low-x. |
Strong Interactions |
|
jamil@tezu.ernet.in |
| 227 |
H1 Collaboration |
Search for Events with an Isolated Tau Lepton and Missing Pt at HERA |
A search for the production of tau leptons in ep-collisions with the
H1 detector at HERA is presented, using the complete H1 dataset taken
in the years 1994-2007, corresponding to an integrated luminosity of
471~pb$^{-1}$. Tau leptons are identified by using an identification
algorithm based on the search for isolated charged tracks associated
to narrow hadronic jets detected in the calorimeters, a typical
signature of the one-prong hadronic tau decay.
|
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 228 |
H1 Collaboration |
Search for Events with an Isolated Lepton and Missing Pt at HERA |
The search for events containing isolated leptons (electrons or muons)
and missing transverse momentum produced in e$^{\pm}$p collisions is
performed with the H1 detector at HERA in the period 1994-2007. The
analysis now examines the complete H1 data sample, corresponding to an
integrated luminosity of 478~pb$^{-1}$, which includes 189~pb$^{-1}$
of $e^{+}p$ data (2003-04 and 2006-07) and 170~pb$^{-1}$ of $e^{-}p$
data (2004-06) from the HERA~II phase. An excess of events compared to
the Standard Model prediction is observed in the $e^{+}$ data at large
hadronic transverse momentum $P_{T}^{X} >$ 25 GeV. Events with large
transverse momentum are observed in both the HERA I and II $e^{+}p$
samples.
|
Physics Beyond the Standard Model |
|
obehnke@mail.desy.de |
| 229 |
H1 Collaboration |
Strangeness production in deep-inelastic scattering at HERA |
The inclusive production cross sections of strange neutral particles in
deep-inelastic ep scattering at HERA are measured with the H1 detector.
The data were taken in the years 1996 to 2000 at a center of mass energy
of 300 - 318 GeV and sum up to a luminosity of 75 pb-1. The cross sections
are determined for the kinematic region of small four-momentum transfer
2 < Q^2< 100 GeV^2 and inelasticity 0.1 < y < 0.6 and the visible range
|\eta(K0_S,\Lambda)| < 1.3 and p_T(K0_S,\Lambda) > 0.5 GeV. The measured
cross sections are compared with different model predictions.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 230 |
H1 Collaboration |
A combined electroweak and QCD analysis at HERA with longitudinally polarised
e^+/e^- beams |
Using the deep inelastic e^+p and e^-p charged and neutral current scattering
cross sections, including data with polarised electron beams, a combined
electroweak and QCD analysis is performed to determine electroweak parameters
accounting for their correlation with parton distributions. The precision
has been improved in particular for u quark coupling to the Z boson
with respect to the published results based on the unpolarized HERA data only.
The determinations from HERA are compared with those from LEP and Tevatron.
|
High-Energy Electroweak Physics |
|
obehnke@mail.desy.de |
| 231 |
H1 Collaboration |
High Q2 Charged Current in polarised ep collisions |
Data taken with electrons of different longitudinal polarisation states in
collision with unpolarised protons at HERA are used to measure the total
cross sections of the charged current process, e^- p -> nu X, for
negative four-momentum transfer squared Q^2 > 400 GeV^2 and inelasticity
y<0.9. Together with the corresponding cross section obtained from
the previously published unpolarised data, the polarisation dependence of
the charged current cross section is measured and found to be in agreement
with the Standard Model prediction. The polarised charged current results
are used to set limits on right-handed charged current interactions.
|
High-Energy Electroweak Physics |
|
obehnke@mail.desy.de |
| 232 |
H1 Collaboration |
High Q2 Neutral Current in polarised ep collisions |
The inclusive single differential cross section ${\rm d}\sigma/{\rm d}Q^2$ and
the reduced double differential cross section $\tilde{\sigma}(x,Q^2)$ are
presented for the neutral current process, $e^{\pm}p \rightarrow e^{\pm} X$,
in interactions with longitudinally polarised lepton beams. The cross sections
are measured in the region of large negative four-momentum transfer squared,
$Q^2 \geq 200\,{ m GeV}^2$ and inelasticity, $y<0.9$. The data are consistent
with the expected $Q^2$ dependence of polarised cross sections.
The reduced cross section data are combined together with previously published
unpolarised data to determine the structure function $x ilde{F}_3$ with
improved precision. The data are compared to predictions of the Standard Model
which is able to provide a good description of the data.
The polarized cross section asymmetries in neutral current are used
to demonstrate parity violating effects in electroweak interactions.
From the dependence of the neutral current cross section on $Q^2$, a
limit on the quark charge radius is extracted.
|
High-Energy Electroweak Physics |
|
obehnke@mail.desy.de |
| 233 |
H1 Collaboration |
Neutral Current Cross Section at High Y and Intermediate $Q^2$ in ep collisions |
A measurement of the reduced double differential cross section
$\tilde{\sigma}(x,Q^2)$ is presented for the neutral current process, $ep$,
at high $0.9>y>0.63$ and intermediate $1000>Q^2>60$~GeV$^2$ range.
The cross section measurement uses complete HERA-II data set and represents
about twofold improvement in precision compared to the previous H1 publication.
The high $y$ cross section is sensitive to the proton structure functions
$F_2$ and $F_L$ and thus provides additional constraint on the gluon
density function. Using DGLAP fit to the lower $Q^2$ H1 data, the contribution
of the $F_L$ structure function to the cross section is determined.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 234 |
H1 Collaboration |
Measurement of the Inclusive ep Scattering Cross Section at low Q^2 and x at HERA |
A new measurement of the inclusive $ep$ scattering cross section is presented
in the region of low four-momentum transfer squared,
$0.2$\,GeV$^2$ $\leq Q2 \leq 8.5$\,GeV$^2$, and low Bjorken $x$,
$4 \cdot 10^{-6} \lesssim x \lesssim 0.02$.
The results are based on two data sets collected in dedicated runs by the H1
Collaboration at HERA at beam energies of 27.6\,GeV and 920\,GeV for positrons
and protons. A combination with data previously published by H1
leads to a scattering cross section measurement of accuracy to a few percent.
The data include the region of high inelasticity $y$ up to 0.85,
which is sensitive to the longitudinal proton structure function $F_L(x,Q2)$.
A reconstruction method based on the use of radiative $ep$ scattering events
extends the measurement to lower $Q2$ and into the domain of larger $x$.
The data are compared with theoretical models which apply to
the transition region from quasi-real photoproduction to deep
inelastic scattering.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 235 |
Chun-Khiang Chua |
Extracting the unitarity angle gamma in Bs to D0 h0, D0bar h0 Decays |
The recently observed color-suppressed B0bar to D0 pi0, D0 eta, D0 eta', Ds+ K-, D0 K0bar, D0 rho0 and D0 omega decay modes all have rates larger than expected. The color-suppressed Bs to D0 phi, D0bar phi modes, which were suggested for the extraction of the unitarity angle gamma in the Gronau-London method, could be larger than the previous estimation by one order of magnitude. Several new theoretical clean modes in Bs decays are suggested for the extraction of gamma. The proposed Bs to D0 h0, D0bar h0 decay modes with h0 = pi0, eta, eta', rho0, omega in addition to h0 = phi are free from penguin contributions. Their decay rates can be estimated from the observed color-suppressed B0bar to D0 h0 rates through SU(3) symmetry. A combined study of these D0 h0, D0bar h0 modes in addition to the D0 phi, D0bar phi modes is useful in the extraction of gamma in the Bs system without involving the Bs-Bsbar mixing. Since the b to u and b to c transitions belong to the same topological diagram, the relative strong phase is likely to be small. In this case, the CP asymmetries are suppressed and the untagged rates are very useful in the gamma extraction. |
Flavour Physics and CP Violation |
"Based on the work published in Phys. Lett. B633, 70-74 (2006)." |
ckchua@cycu.edu.tw |
| 236 |
H1 Collaboration |
Measurement of the Inclusive ep Scattering Cross Section at medium Q^2 and x at HERA |
A new measurement of the inclusive $ep$ scattering cross section is presented
in the region of medium four-momentum transfer squared,
$12$\,GeV$^2$ $\leq Q2 \leq 150$\,GeV$^2$, and low Bjorken $x$,
$4 \cdot 10^{-4} \lesssim x \lesssim 0.1$.
The results are based on the data collected in 2000 with the H1 configuration
optimal for the measurement in this kinematic domain. The accuracy
of the cross section measurement reaches unprecedented in this kinematic
range $1.5-2\%$ level. The new cross section measurement is compared
with the predictions of the DGLAP QCD evolution.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 237 |
H1 Collaboration |
Measurement of the Inclusive ep Scattering Cross Section at low Q^2 and high y at HERA |
A new measurement of the inclusive $ep$ scattering cross section is presented
in the region of low four-momentum transfer squared,
$12$\,GeV$^2$ $\leq Q2 \leq 150$\,GeV$^2$, and very high inelastisity,
$0.75
| Strong Interactions |
|
obehnke@mail.desy.de |
|
| 238 |
H1 Collaboration |
Measurement of diffractive dijet photo-production at HERA |
A new measurement is presented of differential dijet cross section in
diffractive photoproduction (Q^2<0.01 GeV^2) at HERA.
The measurement is based on the data collected with the H1 detector in positron-proton collisions in
years 1999 and 2000 with an integrated luminostiy of ~55 pb^-1.
The results are compared to LO and NLO QCD calculations based on diffractive parton densities
previously obtained from a QCD analysis of inclusive diffractive DIS cross
sections by H1. The event topology is given by ep->eXY in which system X, containing at
least two jets, is separated from a leading-low mass proton dissociative
system Y by a large rapidity gap. The ratio of differential dijet diffractive cross section to
dijet inclusive cross section in photoproduction is measured as a function
of fractional momentum of the photon entering the hard subprocess,
x_gamma, and compared to LO and NLO QCD predictions. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 239 |
H1 Collaboration |
Diffractive photon scattering at large momentun transfer in
photoproduction at HERA |
The diffractive photon scattering with large momentum transfer in
photoproduction regime is measured for the first time at HERA.
The data were collected in $e^+ p$ interactions by
the H1 detector using an integrated luminosity of $43.7\mathrm{pb}^{-1}$.
The analysis is based on a data sample in with photoproduction reactions
are tagged by the detection of the scattered positron in a calorimeter
close to the beam pipe limiting the photon virtuality to $Q^2 < 0.01$
GeV$^2$ and the photon-proton center-of-mass energy, $W$, to the range
$175 < W < 247 \ {\rm GeV}$.
The measured cross section is presented as a function of $W$ and
differentially in $t$ limited to $|t| > 4$ GeV$^2$,
where $t$ is the square of the four-momentum
transferred at the proton vertex.
The results are found to be consistent with a model based on perturbative QCD
calculated using the leading logarithmic approximation of BFKL. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 240 |
ALEPH Collaboration |
Measurement of the cross section of open b production in two-photon interactions at LEP |
Inclusive production of b quarks by two photons has been measured with ALEPH using about 700 pb-1 at centre-of-mass energies between 130 and 209 GeV. |
Strong Interactions |
|
Roberto.Tenchini@cern.ch |
| 241 |
C J Chammasheril and P C Vinodkumar |
Sensitivity of Quark Matter EoS Parameters and Quark Star Properties. |
Understanding of inter-quark interactions is very important not only from high energy physics but also from one of the most enigmatic problem of astrophysics: “The existence of deconfined quark matter inside the neutron star”. Most of the approaches to address this problem are based on phenomenological models for quark interactions. MIT-Bag model [1] and Effective Bag model [2] are very popularly employed models in studies on strange stars and hybrid stars and we have considered these two models for the present study. These models have certain parameters, known only in a range of values. This leads to a situation in which, we get set of equation of state for a given model. It is interesting to study, qualitatively and quantitatively, the influence of these parameters on equations of state and strange and hybrid stars properties obtained using them. For this purpose we define “sensitivity” as fractional change in pressure with respect to fractional change in the parameter of interest and studied the influence of this parameters on pressure. We extend this concept of “sensitivity” to study the influence on strange star and hybrid star properties. Results of our studies, merits and demerits based on "sensitivity" and relevant values of parameters in light of claims of high mass neutron stars will be presented.
[1] Farhi E and Jaff R (1984) Phys. Rev. D 30,2379.
[2] Schertler K, Greiner C, Thoma M (1997) Nucl. Phys.A 616, 659.
|
Astroparticle Physics, Gravitational Waves and Cosmology |
|
clementcj@rediffmail.com |
| 242 |
I.Adachi on behalf of the Belle Aerogel RICH R&D group |
Study of a Proximity Focusing RICH Based on a Silica Aerogel Radiator |
A proximity focusing RICH using a silica aerogel Cherenkov radiator has been developed for new particle identification device in the upgraded Belle detector. To further improve the detector performance, a new concept for Cherenkov ring imaging has been introduced, where multiple aerogel layers with different indices are accumulated to increase the number of detected photoelectrons without making the Cherenkov photon angle resolution worse. By constructing a prototype counter, this idea was validated in a test beam experiment, and
we achieved 5.5 $¥sigma$ $¥pi/K$ separation at 4 GeV/c
with more than 9 photoelectrons. We will demostrate new results from the latest test beam experiment including recent improvements on both of a silica aerogel radiator and a photon detector. |
Detectors and Data Handling |
|
ichiro.adachi@kek.jp |
| 243 |
T. Maki for the CDF Collaboration |
Top quark mass measurement in dilepton channel |
We present a top quark mass measurement using 1.2 fb^-1 of Run II data
collected by the CDF experiment at Fermilab. The measurement uses ttbar
event candidates having two high transverse momentum leptons, at least two
jets and missing transverse energy from escaping neutrinos. Reconstruction
of the top quark mass from dilepton events involves an underconstrained
system. In this analysis, it is resolved by introducing an additional
equation for the longitudinal momentum of the ttbar system. The top quark
mass is reconstructed for each event, and the final result is achieved by
comparing the resulting distribution from data to Monte Carlo templates.
|
High-Energy Electroweak Physics |
|
tmaki@fnal.gov |
| 244 |
H1 Collaboration |
Three- and Fourjet Production in Deep Inelastic ep Scattering and low x Parton Dynamics at HERA |
Differential three- and fourjet cross sections in deep inelastic ep
scattering
at low x and Q^2 have been measured with the H1 detector using
an integrated luminosity of 44.2 pb^{-1}.
Several phase-space regions have been selected for the threejet analysis
in order to study parton dynamics from the most global topologies to the most
restrictive regions of forward
jets (close to the proton-direction).
The measurements of threejet cross sections are
compared with fixed order QCD predictions of
O(\alpha_s^2) and
O(\alpha_s^3)
and with two leading order MC predictions where additional partons are
generated by parton showers
and according to the color dipole model, respectively. A good description of
the threejet cross sections
is given by the
O(\alpha_s^3) prediction for which remaining differences
are concentrated at low x and topologies with two forward jets, which are
most sensitive to unordered gluon radiation.
The LO MC with unordered gluon radiation modeled by the color dipole model
gives a good
description of both the three- and the fourjet data in absolute
normalisation and shape.
These results are interpreted as strong hints for the presence
of large contributions
from gluon radiation not ordered in transverse momentum at
low x and forward rapidities.
|
Strong Interactions |
|
obehnke@mail.desy.de |
| 245 |
Bo Jayatilaka, Chris Hays, Ashutosh Kotwal, Larry Nodulman, Oliver Stelzer-Chilton, William Trischuk, Ian Vollrath |
First Measurement of the W Boson Mass with CDF in Run II |
We describe a measurement of the $W$ boson mass $m_W$ using
$\approx$200 pb$^{-1}$ of $\sqrt{s}$=1.96 TeV $p\bar{p}$ collision
data from the Fermilab Tevatron collected with the CDF II detector.
Using 63,964 $W\rightarrow e\nu$ candidates and 51,128 $W\rightarrow
\mu\nu$ candidates, we measure $m_W = 80.413 \pm 0.034~{\rm (stat)}
\pm 0.034~{\rm (sys)}$ GeV/$c^2$. With a total uncertainty of 0.048
GeV/$c^2$, this is the single most precise $m_W$ measurement to date. |
High-Energy Electroweak Physics |
|
oliversc@fnal.gov |
| 246 |
Belle Collaboration |
Evidence for $D^0--\overline{D}^0$ Mixing |
We observe evidence for $D^0 --\overline{D}^0$ mixing by measuring the
difference in effective lifetime when a $D^0$ meson decays to the $CP$
eigenstates $K^+K^-$ and $\pi^+\pi^-$, and decays to the final state
$K^-\pi^+$. The relative difference of lifetimes is found to be
$y_{CP}=(1.31\pm 0.32({\rm stat.})\pm 0.25({\rm syst.}))\%$. The value
differs from zero by 3.2 standard deviations and hence represents
clear evidence for mixing, regardless of possible CP violation.
We also search for the latter, and find no evidence for it.
These results are based on 540~fb$^{-1}$ of data recorded
by the Belle detector at the KEKB asymmetric $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 247 |
Belle Collaboration |
Study of $D^0--\overline{D}^0$ mixing using Dalitz analysis of |
We report on a study of $D^0--\overline{D}^0$ mixing in
$D^0 \to K_S^0 \pi^+\pi^-$ decays using a Dalitz plot analysis.
The observables in the analysis are
the mixing parameters $x$ and $y$, for which we obtain
$x=(0.80\pm0.29^{+0.09+0.15}_{-0.07-0.14})\%$ and
$y=(0.33\pm0.24^{+0.07+0.08}_{-0.12-0.09})\%$ assuming no $CP$ violation.
The quoted errors are statistical, experimental systematical and systematical
arising from modelling of the Dalitz distribution. Results are based on
540 fb$^{-1}$ of data accumulated by the Belle detector at KEKB.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 248 |
Belle Collaboration |
Study of $\Omega_c^0$ at Belle |
We present a measurement of the $\Omega_c^0$ mass using
a sample of $\Omega^- \pi^+$ decays. We also present preliminary
results of a study of the $\Omega_c^*$ excited state.
The analysis is based on a large data sample recorded at the
$\Upsilon(4S)$ resonance and nearby continuum
with the Belle detector at the KEKB $e^+e^-$ energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 249 |
Belle Collaboration |
Measurement of the near-threshold $e^+e^- \to D\bar{D}$ and |
We report on a measurement of the exclusive $e^+e^- \to
D\bar{D}$, where $D=D0$ or $D^+$, and $e^+e^- \to
{Lambda_c}^{\pm}{Lambda_c}^{\mp}$ cross sections as a function of
center-of-mass energy near the $D \bar{D}$ and
${Lambda_c}^{\pm} {Lambda_c}^{\mp}$ thresholds with initial state
radiation. A full reconstruction technique is used. The analysis is
based on a large data sample collected with the Belle detector at the
$\Upsilon(4S)$ resonance and nearby continuum at the KEKB
asymmetric-energy $e^+ e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 250 |
Belle Collaboration |
A search for new charmonium states above $D\bar{D}$ threshold |
We present a study of the $X(3940)$ state and a further search for other
charmonium states above $D\bar{D}$ threshold recoiling against the
$J/\psi$ in the $e^+ e^-$ annihilation. The analysis is based on a large
data sample recorded at the $\Upsilon(4S)$ resonance and nearby continuum
with the Belle detector at the KEKB $e^+e^-$ energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 251 |
Belle Collaboration |
Study of $D_{s1}(2536)^+$ decays into $D^+\pi^-K^+$ and $D^{* +}K_S$ |
We report the analysis of the decay $D_{s1}(2536)^+ \to
D^+\pi^- K^+$ using 462~fb$^{-1}$ data sample collected with the
Belle detector near the $\Upsilon(4S)$ resonance.
We also study the angular distributions in the
$D_{s1}(2536)^+ \to D^{*+} K^0_S$ decay, measure the relative
D- and S-wave widths and establish the dominance of the latter.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 252 |
Belle Collaboration |
Search for $B^0 \to \Lambda_c^+ \Lambda_c^-$ decay at Belle |
We search for the double charmed baryonic decay
$B^0 \to \Lambda_c^+\Lambda_c^-$.
This analysis is based on a large data sample accumulated at the
$\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 253 |
Belle Collaboration |
Study of intermediate two-body decays in $\bar{B}^0\to \Sigma_c(2455)^{0}\bar{p}\pi^{+}$ decay. |
We study the three-body decay
$\bar{B}^0\to \Sigma_c(2455)^{0}\bar{p}\pi^{+}$, and observe a broad
mass structure in the $\bar{p}\pi^+$ system near $1.5\,{\rm GeV}/c2$.
This structure is due to the two-body cascade decay
$\bar{B}^0\to \Sigma_c(2455)^{0} (\bar{p}\pi^{+})$.
This analysis is based on a data sample of 357 fb$^{-1}$, accumulated at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric
$e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 254 |
Belle Collaboration |
Measurement of ${\cal B}(D_s^+ \to \mu^+ \nu_mu)$ |
We present a study of $D_s$ decays to $\mu \nu_\mu$
using a large data sample collected by the Belle experiment at
the KEKB $e^+ e^-$ collider. The $D_s$ decays are tagged by
fully reconstructing events of
the type $e^+e^- \to D_s D K X$, where X represents additional
charged and neutral particles.
The reconstruction method provides good resolution in the
neutrino momentum and thus also good background separation.
The absolute value of ${\cal B}(D_s^+\to\mu^+\nu_\mu)$ is determined.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 255 |
Belle Collaboration |
Measurement of ${\cal B}(D0\to \pi^+\pi^- \pi^0)/{\cal B}(D0 \to K \pi \pi^0)$ |
We present the results of the precise measurement of
${\cal B}(D0 \to \pi^+ \pi^- \pi^0)$/${\cal B}(D0 \to K \pi \pi^0)$
using a large data sample collected with the Belle
detector at the $\Upsilon(4S)$.
We also searched for the $CP$ violation in this decay by measuring
the asymmetry
$A=({\cal B}(D0 \to \pi^+ \pi^- \pi^0) - {\cal B}(\bar{D0} \to \pi^+
\pi^- \pi^0))/({\cal B}(D0 \to \pi^+ \pi^- \pi^0) + {\cal B}(\bar{D0}
\to \pi^+ \pi^- \pi^0))$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 256 |
Belle Collaboration |
Study of $X(3872)$ production in neutral $B$ meson decays. |
The diquark anti-diquark model
of Maiani, Piccinini, Polosa and Riquer predicts
that the observed $X(3872)$ is one component of
a doublet of states. In this model, the $``X(3872)''$
produced in neutral $B$ meson decays will have a mass
that is different from its counterpart in charged $B$
meson decays by $\Delta M = (7 \pm 2~{\rm MeV}/\cos 2\theta$,
where $\theta$ is a mixing angle that is near $\pm 200$.
We report results of studies of the properties of $X(3872)$
mesons produced via neutral and charged $B$ meson decay modes.
The results are based on an analysis of a large
data sample collected at the $\Upsilon(4S)$ resonance
with the Belle detector operating at the KEKB
asymmetric energy $e^+e^-$ storage rings.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 257 |
Belle Collaboration |
Search for lepton flavor violating $\tau$ decays to 3 leptons |
We report results of a search for lepton flavor violating $\tau$
decays into 3 lepton final states using a large data sample
accumulated with the Belle detector at the KEKB $e^+ e^-$
collider. The sensitivity for these processes has improved
considerably compared to previous experimental results.
|
Physics Beyond the Standard Model |
|
Yoshihide.Sakai@kek.jp |
| 258 |
Belle Collaboration |
Search for lepton flavor violating $\tau\to l V^0$ decays at Belle |
We report results for $\tau$ decays lepton and a neutral vector
meson using more 500 fb$^{-1}$ of data. We have
improved the sensitivity for the processes by a factor of two compared
to previous experimental results and obtained the first limits
for the modes $\tau \to \mu/(e) \omega$.
|
Physics Beyond the Standard Model |
|
Yoshihide.Sakai@kek.jp |
| 259 |
Belle Collaboration |
Precise measurement of $\tau$ hadronic decays in modes with $\eta$ mesons |
Precise measurements of branching fractions for $\tau$
hadronic decays involving an $\eta$ meson are presented for a large
dataset currently available with the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 260 |
Belle Collaboration |
Study of $\tau^-\to K_S \pi^-\nu_{\tau}$ decay at Belle. |
We present a study of $\tau^-\to K_S \pi^-\nu_{\tau}$ decay
using a data sample corresponding to an integrated
luminosity of $351\ \rm{fb^{-1}}$ collected with the Belle detector.
The analysis is based on $53110$ lepton-tagged signal events.
The measured branching ratio
is consistent with the world average value and has better accuracy.
An analysis of the $K_S\pi$ invariant mass spectrum
reveals contributions from the $K^*(892)$ as well
as other states. For the first time $K^*(892)$ mass and width have been
measured in $\tau$ decay.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 261 |
Belle Collaboration |
Evidence for CP Violation in B^0 -> D^+D^- Decays |
We report measurements of the branching fraction and $CP$ violation
parameters in $B^0 \to D^+ D^-$ decays. The results are based on a
data sample that contains $535 \times 10^6$ $B\overline{B}$ pairs
collected at the $\Upsilon(4S)$ resonance, with the Belle detector at
the KEKB asymmetric-energy $e^+ e^-$ collider. We obtain
$ \left[1.97 \pm 0.20 \,\textrm{(stat)}\, \pm 0.20\,\textrm{(syst)}\,\right]
\,\times 10^{-4} $ for the branching fraction of $B^0 \to D^+D^-$.
The measured values of the $CP$ violation parameters are:
\mbox{$\mathcal S = -1.13 \, \pm 0.37 \,\pm 0.09$}, \mbox{$\mathcal A
= 0.91 \, \pm 0.23 \,\pm 0.06$}, where the first error is statistical
and the second is systematic. We find evidence of $CP$ violation in
$B^0 \to D^+ D^-$ at the $4.1\,\sigma$ confidence level. While the
value of $\mathcal S$ is consistent with expectations from other
measurements, the value of the parameter $\mathcal A$ favors large
direct $CP$ violation at the $3.2\,\sigma$ confidence level, in
contradiction to Standard Model expectations.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 262 |
Belle Collaboration |
Improved measurement of $\bbar\to D_s^-D^+$ and search for $\bdsds$ at Belle |
We reconstruct $\bbar\to D_s^-D^+$ decays using a sample of
$449\times 10^6$~$B\overline{B}$ pairs recorded by the Belle
experiment, and measure the branching fraction to be
${\cal B}(\bbar\to D_s^-D^+)=\bigl[7.5\pm 0.2({\rm stat})
\pm 0.8({\rm syst})\pm 0.8({\rm {\cal B}'s})\bigr]\times 10^{-3}$.
A search for the related decay $\bdsds$ is also performed.
Since we observe no statistically significant signal an upper
limit on the branching fraction is set at $3.6\times 10^{-5}$
(90\% C.L.).
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 263 |
Belle Collaboration |
Study of $B^0 \to \chi_{c1} \pi^0$ at Belle |
We report results of a search for the decay of the neutral $B$ meson
into the final state $\chi_{c1} \pi^0$, a Cabibbo- and color-suppressed
decay. The results are based on a
large data sample of $B\overline B$ events collected at
the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB
asymmetric energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 264 |
Belle Collaboration |
Study of $B^0 \to J/\psi \pi^+ \pi^-$ decays with 449 million |
We report a study of $B^0 \to J/\psi \pi^+ \pi^-$ decay with
a data sample collected by the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider. The pion pair can be produced
via resonances ($\rho^0, f_2$ etc.) as well as by a non-resonant
process. We measured not only the total branching fraction but also the
individual resonant contributions.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 265 |
Belle Collaboration |
Measurement of $CP$-violation parameters in $B^0 \to J/\psi \pi^0$ |
$CP$-violation parameters for neutral $B$ meson decays into the
$J/\psi \pi^0$ final state are measured with a large sample of
$\bar{B} B$ pairs recorded by the Belle detector at the KEKB
$e^+ e^-$ energy asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 266 |
Belle Collaboration |
Measurements of time-dependent $CP$ asymmetries in radiative $B^0$ Decays |
We present measurements of $CP$-violation parameters in radiative decays
of $B^0$ using a large sample of $B\bar{B}$ pairs recorded at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB
asymmetric energy $e^+e^-$ collider. $CP$-violation parameters are
obtained from the asymmetries in the distributions of the proper-time
intervals between the reconstructed $B$ and the accompanying $B$ meson.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 267 |
Belle Collaboration |
Measurements of time-dependent $CP$ asymmetries in hadronic penguin $B^0$ Decays |
We present measurements of $CP$-violation parameters in $b \to s q\bar{q}$
and $b \to d q\bar{q}$ decays using a large sample of $B\bar{B}$ pairs
recorded at the $\Upsilon(4S)$ resonance with the Belle detector at the
KEKB asymmetric energy $e^+e^-$ collider. $CP$-violation parameters are
obtained from the asymmetries in the distributions of the proper-time
intervals between the reconstructed $B$ and the accompanying $B$ meson.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 268 |
Belle Collaboration |
Measurement of $\phi_3$ from a Dalitz plot analysis of $B^+ \to D^{(*)} K^{(*)+}$ decay |
We present an updated measurement of the unitarity
triangle angle $\phi_3$ using Dalitz plot analysis of three-body
neutral $D$ decays from $B\to D^{(*)}K^{(*)}$ process. The results
are based on a large
sample of $B\bar{B}$ pairs recorded at the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 269 |
Belle Collaboration |
Study of the Suppressed Decays $B^- \to D^{(*)} K^{(*)-}$ at Belle |
We report studies of the suppressed decays $B^- \to D^{(*)}K^{(*)-}$.
These modes play an important role in the extraction of the CKM angle
$\phi_3$ (via the Atwood-Dunietz-Soni (ADS) method). A data sample
recorded at the $\Upsilon$(4S) resonance by the Belle experiment at
the KEKB asymmetric energy $e^+ e^-$ collider is used to give constraints
on $\phi3$ and $r_B \equiv |A(B^- \to \bar{D^0}K^-)/ {A(B^-\to D^0K^-)|$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 270 |
Belle Collaboration |
Improved Measurements of $B\to D_s K$ and $B\to D_s\pi$ Branching Fractions |
We report improved measurements of the $B\to D_s^{(*)} K$ and
$B\to D_s^{(*)}\pi$ branching fractions. The results are based on a
large data sample recorded at the $\Upsilon$(4S) resonance by the
Belle experiment at the KEKB asymmetric energy $e^+ e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 271 |
Belle Collaboration |
Study of $B^+ \to D^{(*)+} \pi^0$ decay and the ratio of suppressed and favoured amplitudes in $B \to D^{(*)}\pi$ decays. |
We report results of a search for $B^+ \to D^{(*)+} \pi^0$ decay
using a large data sample collected at the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric energy $e^+ e^-$
collider. We use the results to constrain the ratio of suppressed
and favoured amplitudes in $B \rightarrow D^{(*)}\pi$ decays
using the relation,
$R_{D^{(*)}\pi} = \frac{2Br(B^+ \rightarrow D^{(*)+} \pi^0)}
{Br(B^0 \rightarrow D^{(*)+} \pi^-)}$. This gives important information
needed for the extraction of $\sin(2 \phi_1 +\phi_3)$ from time-dependent
$B^0\to D^{(*)-}\pi^+$ decays.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 272 |
Belle Collaboration |
Study of $B^0 \to a_1^{\pm}\pi^{\mp}$ decays. |
We present a study of $B^0 \to a_1^{\pm}\pi^{\mp}$, which
is a decay mode sensitive to the Cabibbo-Kobayashi-Maskawa
weak phase angle $\phi_2$. The results are based on a large data sample
collected with the Belle detector
at the KEKB asymmetric energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 273 |
Belle Collaboration |
Measurements of the Branching Fractions of $B^0 \to \rho(770)^+\pi^-$, $\rho(770)^-\pi^+$, and $\rho(770)^0\pi^0$ Decays. |
We present a measurement of the branching fractions of $B^0 \to
\rho(770)^+\pi^-$, $\rho(770)^-\pi^+$, and $\rho(770)^0\pi^0$ decays based
on a 414/fb data sample containing 449M $B\overline{B}$ pairs collected by
the Belle detector at the KEKB asymmetric-energy $e^+e^-$
collider. The results include the first measurement of the
branching fractions of $B^0 \to \rho(770)\pi$
with the contributions from radial excitations, $\rho(1450)$ and
$\rho(1700)$, removed using a Dalitz plot analysis.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 274 |
Belle Collaboration |
Search for the decay $B \to X(3872) K$ with $X(3872) \to D^{*0} \overline{D}^0. |
We report a search for $B \to X(3872) K$ with $X(3872)$
decaying to $D^{*0} \overline{D}^0 using a large sample of
$B\bar{B}$ pairs recorded at the $\Upsilon(4S)$ resonance with the
Belle detector at the KEKB asymmetric energy $e^+e^-$ collider.
The study is performed separately for the $D^{*0} \to D^0 \gamma$ and
$D^{*0} \to D^0 \pi^0$ decay modes.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 275 |
Belle Collaboration |
Search for the decays $B \to D_{sJ}(2536) D^{(*)}$. |
We report a search for $B \to D_{sJ}(2536) D^{(*)}$
with the $D_{sJ}(2536)$ decaying to $D^{*0} K^+$ and $D^{*+} K_S$.
The study is performed using a large sample of $B\bar{B}$ pairs
recorded at the $\Upsilon(4S)$ resonance with the Belle detector at
the KEKB asymmetric energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 276 |
Belle Collaboration |
Measurements of the branching fraction, polarization and $CP$ violation parameters for the decay $B^0 \to D^{*+} D^{*-}$. |
We report measurements of the branching fraction, polarization
and $CP$-violation parameters for the decay $B^0 \to D^{*+}D^{*-}$.
The results are based on a data collected at the $\Upsilon(4S)$
resonance with the Belle detector at the KEKB asymmetric-energy
$e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 277 |
Belle Collaboration |
Study of the time-dependent decay rate of $B_s^0$ meson |
We report a study of the time-dependent decay rate of $B_s^0$ meson.
The results are based on a 22 $fb^{-1}$ data collected at the
$\Upsilon(5S)$ resonance with the Belle detector at the KEKB
energy-asymmetric $e^+e^-$ collider.
We measure the $B_s^0$ lifetime from the proper-time difference
distribution of the two $B_s^0$ meson decays using exclusively
reconstructed hadronic decays as well as dilepton events.
The decay width difference for the two mass eigenstates of the
$B_s^0$ -$\bar B_s^0$ system, $\Delta \Gamma_s / \Gamma_s$, appears
in a term proportional to the $\cosh$ of the proper-time difference.
In this analysis,
we employ techniques similar to those established in measurements
of the $CP$-violating parameters for $B_d^0$ decays.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 278 |
Belle Collaboration |
Search for $B_s \to \phi \gamma$ and $B_s \to \gamma\gamma$ at Belle |
We report on searches for $B_s \rightarrow \phi \gamma$ and $B_s
\rightarrow \gamma \gamma$ decays using a 22 $fb^{-1}$ data sample recorded
at the $\Upsilon(5S)$ resonance by the Belle detector at the KEKB $e^+e^-$
energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 279 |
Belle Collaboration |
Measurement of inclusive semileptonic $B_s \to X l \nu$ decay. |
The correlated production at the $\Upsilon$(5S) resonance
of a $D_s$ meson and a lepton of the same sign is studied.
The branching fraction for the inclusive decay $B_s \rightarrow X l \nu$
is measured for the first time.
The analysis is based on a 22 $fb^{-1}$ data sample recorded at
the $\Upsilon(5S)$ resonance with the Belle detector at the
KEKB $e^+e^-$ energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 280 |
Belle Collaboration |
Measurement of branching fractions for $B_s^0\rightarrow J/\psi \phi$ and $B_s^0\rightarrow J/\psi K_s^0$ decays at $\Upsilon(5S)$ |
We measure the branching fractions for $B_s^0\rightarrow J/\psi
\phi$ and $B_s^0\rightarrow J/\psi K_s^0$ decays using a
22 $fb^{-1}$ data sample collected on the $\Upsilon(5S)$
resonance by the Belle detector at the KEKB asymmetric energy
$e^+e^-$ collider. The $J/\psi$ candidates are reconstructed
from both $e^+e^-$ and $\mu^+\mu^-$ pairs; $\phi$ candidates are
reconstructed from $K^+K^-$ pairs and $K_s^0$ candidates from
$\pi^+\pi^-$ pairs.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 281 |
Belle Collaboration |
Search for $B\to f_{0} K^{*0}$ decay |
We report the results of a search for $B\to f_{0} K^{*0}$ decays.
The results are based on a dataset collected with the Belle detector
at the KEKB asymmetric-energy
$e^+e^-$ collider at the $\Upsilon(4S)$ resonance.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 282 |
Belle Collaboration |
Improved measurements of $B\to \rho\gamma$ and $B\to\omega\gamma$ |
We report the results of improved branching fraction measurements for
$B^+\to \rho^+\gamma$, $B^0 \to \rho^0\gamma$ and $B^0 \to \omega\gamma$
using a large dataset collected with the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider. We also measure the charge
asymmetry of $B^+\to \rho^+\gamma$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 283 |
Belle Collaboration |
Measurement of the Branching Fraction for $B\to\eta'K\gamma$ Decays |
We present a measurement of the branching fraction for
$B \to\eta^{'} K \gamma$ decays based on a large data sample
recorded at the $\Upsilon(4S)$ resonance with the Belle detector
at the KEKB $e^+e^-$ energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 284 |
Jacob Linacre for the CDF collaboration |
Measurement of the Top Quark Mass using the Matrix Element Analysis Technique in the Lepton + Jets Channel with In Situ W to jj Calibration |
We present a top quark mass measurement from ppbar collisions at 1.96 TeV at CDF. We use events from ppbar to ttbar in the lepton+jets channel requiring one charged lepton, high missing transverse energy and exactly 4 jets, at least one of which must be identified as a b-jet. The top quark mass is extracted with a 2D unbinned likelihood fit using per-event probabilities calculated using signal (ttbar) and background (W+jets) matrix elements. The probabilities are a function of both the top quark mass and the energy scale of the calorimeter jets (JES) which is measured in-situ by constraining the invariant mass of two hadronic jets to the W boson mass. |
High-Energy Electroweak Physics |
|
linacre@fnal.gov |
| 285 |
Belle Collaboration |
Improved Measurement of the Differential Decay Rate for $B \to K^{(*)} \ell \ell$ |
Using a large data sample collected with the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider, we present an improved measurement
of the differential decay rate for $B \to K^{(*)} \ell \ell$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 286 |
Belle Collaboration |
Study of $B^+\to p\bar{\Lambda} \gamma$, $B^+\to p \bar{\Lambda} \pi^0$ and $B^0\to p\bar{\Lambda} \pi^-$ |
We study the charmless baryonic three-body decays of $B$ mesons: $B^+
\to p\overline{\Lambda}\gamma$, $B^+ \to p\overline{\Lambda}\pi^0$ and
$B^0 \to p\overline{\Lambda}\pi^-$. The partial branching fractions as
a function of the baryon-antibaryon mass and the polar angle
distributions of the proton in the baryon-antibaryon system are
presented. These results are obtained from a large data sample that was
collected near the $\Upsilon(4S)$ resonance with the Belle detector at
the KEKB asymmetric energy $e^+ e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 287 |
Belle Collaboration |
Study of $B^+\to p\bar{p} K^+$ and $B^+\to p\bar{p} \pi^+$ |
We study the decays $B^+\to p\bar{p} K^+$ and $B^+\to p\bar{p} \pi^+$,
especially for the polar angle distributions of the
proton in the proton-antiproton helicity frame. This is useful for
understanding the nature of the observed $M_{p\overline{p}}$ peaks near
threshold. We also set upper limits on the branching fractions of the
intermediate two-body decays, $\B^+ \to \Delta^{++} \bar{p}$ and
$\B^+ \to p \bar{\Delta}{}^0$, for the $p\bar{p} \pi^+$ final
state at the 90\% confidence level. These results are obtained from a
large data sample that was collected near the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric energy $e^+ e^-$
collider. |
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 288 |
Belle Collaboration |
Measurement of $B \to D_s^{(*)} K\pi$ branching fractions |
Exclusive $B$ meson decays to the final states $D_s^{(*)} K\pi$ are
studied using a large data sample collected at the $\Upsilon(4S)$
resonance by the Belle dete ctor at KEKB. The branching fractions for
$B^+\to D_s^-K^+\pi^+$ and $B^+\to D_s^{*-}K^\ +\pi^+$ are determined.
A study of the two-body $D_sK$ and $D_s\pi$ subsystems is also performed.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 289 |
Belle Collaboration |
Search for $B$ decays to $B\to K^{(*)} \nu \bar{\nu}$ using one fully reconstructed $B$ meson |
We present a search for B decays to $B\to K^{(*)} \nu \bar{\nu}$ using
one fully reconstructed B meson in the final state. This study is based
on a large data sample recorded at the $\Upsilon(4S)$ resonance with the
Belle detector at the KEKB energy-asymmetric $e^{+}e^{-}$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 290 |
Belle Collaboration |
Measurement of the Photon Energy Spectrum of Inclusive Radiative B-meson Decays |
Using a large data sample of $\Upsilon(4S)$ decays to B-meson pairs, we
measure the photon energy spectrum of inclusive radiative B-meson
decays. We determine the partial branching fraction, mean and variance
of the spectrum as a function of the lower threshold photon energy
requirement. The results are based on a data sample collected by the
Belle detector at the KEKB asymmetric energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 291 |
Belle Collaboration |
Updated Measurement of the Branching Fraction for $B \to \phi K \gamma$ and Search for $B \to \omega K \gamma$ at Belle |
Updated branching fractions for $B \to \phi K \gamma$ are
presented for the large dataset currently available with the Belle
detector at the asymmetric-energy $e^+e^-$ collider KEKB. First results
for the decay $B \to \omega K \gamma$ are also presented.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 292 |
Belle Collaboration |
Measurement of the Rare B Decay $B^0 \to \rho^0 \rho^0$ at Belle |
We present a measurement of $B^0 \to \rho^0 \rho^0$. This decay mode
can help us to complete an isospin analysis of $B \to \rho \rho$, which
provides a direct measurement of the CKM angle $\phi_2$. The results are
based on a large data sample collected by the Belle detector at the KEKB
asymmetric energy $e^+ e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 293 |
Belle Collaboration |
Measurement of the Branching Fraction and $X_s$ Mass Spectrum for Inclusive $B\to eta^{'} X_s$ Decays |
Using a large data sample of $B\bar{B}$ pairs collected with the Belle
detector at the KEKB asymmetric-energy $e^+e^-$ collider, we report a
measurement of the branching fraction and $M(X_s)$ spectrum of the
inclusive process $B\to X_s \eta^{'}$ with a semi-inclusive analysis
method.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 294 |
Belle Collaboration |
Observation of $\bar{B}^0\to\D_s^+ \Lambda \bar{p}$ Decay |
We report the first observation of the decay $\bar{B}^0 \to D_s^+
\Lambda \bar{p}$ and a measurement of its branching fraction. This
charmful baryonic B decay proceeds via a $b\to c \bar{u} d$ transition
with popping of an $s \bar{s}$ quark pair from the vacuum. The data used
for this analysis was recorded at the $\Upsilon(4S)$ resonance, using
the Belle detector at the KEKB $e^+ e^-$ asymmetric-energy collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 295 |
Belle Collaboration |
Search for $B^0\to K^{*0} \omega$ Decays at Belle |
We present a search for $B \to K^{*0}\omega$ decays based on a large
data sample recorded at the $\Upsilon(4S)$ resonance with the Belle
detector at the KEKB $e^+e^-$ energy-asymmetric collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 296 |
Belle Collaboration |
Search for $B^+ \to \rho^+ \omega$ at Belle |
We report the results of a search for the charmless decay $B^+ \to
\rho^+ \omega$. The analysis is based on a large data sample recorded
at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^+
e^-$ storage ring.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 297 |
Belle Collaboration |
Study of $B \to p \overline{p} K^*$ |
We study the $B \to p \overline{p} K^*$ decays of $B$ mesons. The
branching fractions as well as the polar angular distributions of the
proton in the baryon-antibaryon system are presented. This study is
based on a large data sample recorded on the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 298 |
Belle Collaboration |
Determination of $|V_{cb}|$ and $m_b$ from inclusive semileptonic $B$~decays at Belle |
We present an analysis of the Belle measured moments of the lepton
energy and hadronic mass spectra in B -> X_c l nu decays and the
photon energy spectrum in B -> X_s gamma decays using theoretical
expressions derived in two different frameworks. We determine the
CKM matrix element $|V_{cb}|$, the $b$~quark mass and other
non-perturbative parameters that appear in the description of
inclusive $B$~decays.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 299 |
Belle Collaboration |
Determination of the Form Factors for the Decays $B^0\to D^{*-}\ell^+\nu$ and $ $B^0\to D^-\ell^+\nu$ and extraction of the CKM matrix element $|V_{cb}|$ at Belle |
We present a measurement of the form factors $\rho^2$, $R_1$, and
$R_2$ ($\rho^2$), which describe the decay $B^0\to D^{*-}\ell^+\nu$
($B^0\to D^-\ell^+\nu$) using fully reconstructed events. We also
determine the rate normalization at zero recoil, which we use to
extract the CKM matrix element $|V_{cb}|$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 300 |
Belle Collaboration |
Search for $B\to D^{(*)}\tau\nu$~decays at Belle |
We report the results of a search for the decay $B\to D^{(*)}\tau\nu$.
The analysis uses a large data sample collected at the
$\Upsilon(4S)$~resonance with the Belle detector at the KEKB
asymmetric energy $e^+e^-$~collider.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 301 |
Belle Collaboration |
Measurement of $B\to D^{**}\ell\nu$ at Belle |
We report measurements of the branching ratios of semileptonic
$B$~decays to $P$-wave $D^{**}$~mesons at Belle. The result is
obtained using the full reconstruction tagging method. This method
gives both good separation of decay modes as well as background
suppression.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 302 |
Belle Collaboration |
Measurements of Inclusive $B\to X_u\ell\nu$~decays and constrains on weak annihilation, using the full reconstruction tag at Belle |
We present measurements of the first and second moments of the $q^2$
and hadron mass distribution, and partial branching fraction of
charmless semileptonic B decays. These results are obtained from a
large data sample of $B\overline{B}$~pairs
collected by the Belle detector at the KEKB $e^+e^-$~collider. Events
are tagged by fully reconstructing one of the $B$~mesons. Multivariate
machine learning techniques are used to distinguish the $b\to u$
semileptonic decay from the $b\to c$ semileptonic background. From
these measurements we place a limit on the weak annihilation
contribution to the $B\to X_u\ell\nu$~rate, and determine the
magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, $|V_{ub}|$.
|
Flavour Physics and CP Violation |
|
Yoshihide.Sakai@kek.jp |
| 303 |
Belle Collaboration |
Improved measurement of CP-violating parameters in rho+rho- decays |
We present a measurement of the CP-violating asymmetry in rho+rho- decays using 535 million BBbar pairs collected with the Belle detector at the KEKB e+e- collider. We measure CP-violating coefficients A = 0.16 +- 0.21(stat) +- 0.07 (syst) and S = 0.19 +- 0.30(stat) +- 0.07 (syst}. These values are used to determine the unitarity triangle angle phi_2 using an isospin analysis; the solution consistent with Standard Model lies in the range 53 < phi_2 < 114 deg. at 90 C.L.
|
Flavour Physics and CP Violation |
BELLE-CONF-0678 |
Yoshihide.Sakai@kek.jp |
| 304 |
Belle Collaboration |
Measurement of EPR-type flavor entanglement in Y(4s)->B0B0bar decays |
The neutral B-meson pair produced at the Upsilon(4S) should exhibit
a non-local correlation of the type discussed by Einstein, Podolski,
and Rosen (EPR). We measure this correlation using the
time-dependent flavour asymmetry of semileptonic B0 decays, which we
compare with predictions from quantum mechanics and two local
realistic models. The data are consistent with quantum mechanics,
and inconsistent with the other models. Assuming that some B pairs
disentangle to produce B0 and B0bar with
definite flavour, we find a decoherent fraction of 0.029+-057, consistent with no decoherence. |
Flavour Physics and CP Violation |
BELLE-CONF-0678 |
Yoshihide.Sakai@kek.jp |
| 305 |
Marcin Stolarski on behalf of COMPASS Collaboration |
COMPASS resutls based on spin longitudinal asymmetries |
New COMPASS results of spin longitudinal asymmetries obtained in inclusive
and semi-inclusive inelastic scattering using polarized 160 GeV/c muon beam off deuteron target are presented. The data have been collected between 2002-2004. Measurements cover wide kinematical range: x from 0.00004 to 0.7
and Q^2 between 0.002-100 GeV^2/c^2.
The statistical precision of the asymmetries, especially in the low x domain,is increased considerably compared to the previous experiments. The value of the first moment of g1(x) and the results of the QCD fits in the NLO approximation on all g1 deep inelastic data are shown. The evaluation of the polarized valence
quark distribution, obtained from semi-inclusive data, is also presented. |
Strong Interactions |
|
Marcin.Stolarski@cern.ch |
| 308 |
Stefan Antusch |
Neutrino Mixing Sum Rules |
We discuss the neutrino mixing sum rule
$\theta_{12} - \theta_{13}\cos(\delta)\approx \theta^\nu_{12}$
which provides a possibility to explore the structure of the neutrino
mass matrix in the presence of charged lepton corrections, since it
relates the 1-2 mixing angle from the neutrino mass matrix,
$\theta_{12}^\nu$, to observable parameters of the PMNS mixing matrix.
The neutrino mixing sum rule holds if the charged lepton mixing angles
are CKM-like, i.e., small and dominated by a 1-2 mixing, and for small
1-3 mixing in the neutrino mass matrix. These conditions hold in a wide
class of well motivated flavour models.
As explicit examples, we use the sum rule to test the hypotheses of
tri-bimaximal and bimaximal neutrino mixing, where $\theta^\nu_{12}$
is predicted by $\sin^2(\theta^\nu_{12}) = 1/3$ or $1/2$.
We confront the these hypotheses with present neutrino oscillation
data and discuss the potential of future long-baseline reactor and
accelerator experiments for testing predictions for $\theta^\nu_{12}$.
|
Neutrino Physics |
|
antusch@delta.ft.uam.es |
| 309 |
Stefan Antusch |
Flavour-Dependent Leptogenesis |
We discuss flavour-dependent effects in thermal leptogenesis,
which are shown to have important consequences for the estimation of
the produced baryon asymmetry in many cases of physical interest.
For example, we analyse constraints on the parameters of the
supersymmetric type-I seesaw mechanism from the requirement of
successful thermal leptogenesis in the presence of upper bounds on
the reheat temperature $T_\mathrm{RH}$ of the early Universe. To
this end, we solve the flavour-dependent Boltzmann equations in
the MSSM, extended to include reheating.
We then discuss thermal leptogenesis in classes of neutrino mass models
based on the seesaw mechanism with three right-handed
neutrinos and sequential right-handed neutrino dominance.
Within these classes of models we investigate
constraints and expectations on the individual decay asymmetries and
washout parameters from the present data on neutrino masses and mixings.
We furthermore establish and analyze the link between the leptonic CP
violating phase $\delta$, observable in neutrino oscillations, and the
CP violation required for leptogenesis, where flavour-dependent effects
have a significant effect. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
antusch@delta.ft.uam.es |
| 310 |
A. Geiser and E. Nuncio-Quiroz, DESY and Hamburg University, Germany |
The FMNRxPYTHIA interface for heavy quark production at HERA |
A method to calculate heavy flavor visible-level
cross sections at Next-to-Leading Order (NLO) in
Quantum Chromodynamics (QCD), based on an
interface of the FMNR program to PYTHIA, is described.
It uses the NLO prediction at quark level provided by FMNR, applying a statistical
reduction procedure (REDSTAT) that allows the
link to PYTHIA 6.2, from where the description of
the full hadron fragmentation and decay chain
is obtained.
The method is applied to ep -> bbbarX -> D* mu X
and mu mu final states at HERA.
Comparisons of the data and NLO cross sections at visible and b-quark level were found to be
consistent and equivalent.
|
Strong Interactions |
|
Achim.Geiser@desy.de |
| 311 |
D. Berge on behalf of the ATLAS Trigger Configuration group |
The configuration system of the ATLAS Trigger |
The ATLAS detector at CERN's LHC will be exposed to proton-proton collisions at a rate of 40 MHz. To reduce the data rate, only potentially interesting events are selected by a three-level trigger system. The first level is implemented in custom-made electronics, reducing the data output rate to less than 100 kHz. The second and third trigger levels are realised in software with an output rate of 100-200 Hz. A system has been designed and implemented that hosts and records the configuration of all three trigger levels at a centrally maintained location. This system consistently provides configuration information to the online trigger for the purpose of data taking as well as to the offline trigger simulation. The use of relational database technology provides means of flexible information browsing, easy information distribution across the ATLAS reconstruction sites, and reliable recording of the trigger configuration history over the lifetime of the experiment. The functionality of this design has been demonstrated in dedicated configuration tests of the ATLAS level-1 central trigger and of a 600-node software trigger computing farm. We present an overview of the main system components, including a sophisticated, JAVA-based front-end to populate and maintain the configuration information, and report on the current status of the trigger configuration system. |
Detectors and Data Handling |
|
berge@cern.ch |
| 312 |
Morgan Wascko (for the SciBooNE Collaboration) |
First Data from SciBooNE |
The SciBooNE experiment will measure muon neutrino and antineutrino cross sections on carbon near 1 GeV with unprecedented precision. SciBooNE uses the Booster Neutrino Beam at Fermilab and the SciBar vertex detector formerly used in the K2K experiment at KEK. SciBooNE will start its data run in antineutrino mode in June, 2007. Physics potential of the experiment and first data will be shown. |
Neutrino Physics |
|
m.wascko@imperial.ac.uk |
| 313 |
D. Berge on behalf of the ATLAS first-level trigger community |
The ATLAS Level-1 Trigger: Status of the System and First Results from Cosmic-Ray Data |
The ATLAS detector at CERN's Large Hadron Collider will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system was designed to select potentially interesting events and reduce the incoming rate to 100-200 Hz. The first trigger level (LVL1) is implemented in custom-built electronics. A trigger decision is made by the central-trigger processor yielding a LVL1 output rate of less than 100 kHz. The total allowed latency for the LVL1 decision is less than 2.5 microseconds. The decision is based on calorimeter information and hits in dedicated muon-trigger detectors. Installation of the final LVL1 trigger system at the ATLAS site is in full swing, to be completed later this year. We present an overview of the system and describe the current installation and commissioning status at the experimental site. Integration tests of the central-trigger processor with the calorimeter and muon systems and the level-2 trigger have been successfully performed. Cosmic-ray data have been recorded in situ exercising the full trigger chain, using the central trigger to initiate the read-out of sub-detectors. These data are used for consistency checks of the full hardware and software chain. We show the analysis results and verify, where possible, that the LVL1 trigger meets the requirements and will be ready for data taking. |
Detectors and Data Handling |
|
berge@cern.ch |
| 314 |
Achim Geiser, DESY Hamburg |
Prediction m_H = 2M_W, fermion mass relations and electroweak physics at LHC |
The Standard Model Higgs Yukawa couplings are reexamined in the context
of a composite model. The Higgs mass is predicted to be twice the W mass,
M_H = 2M_W. Mass relations to and between the Standard Model fermions can
also be obtained. Observable consequences for electroweak physics at LHC are
discussed.
|
High-Energy Electroweak Physics |
"Could also be interesting for the Beyond the Standard Model session, although observable effects are essentially within the Standard Model." |
Achim.Geiser@desy.de |
| 315 |
Ekaterina Fadeeva, 6-m MIS ITEP Collaboration, Institute of Theoretical and Experimental Physics, Moscow, Russia |
Investigation of Narrow Resonance at 1450 MeV in the System of Two K_S Mesons |
Results are presented that were obtained by studying narrow resonance of mass about 1450 MeV.
The system of two K_S-mesons has been analyzed in the mass interval 1300-1600 MeV. The experimental data subjected to the analysis come from 6-m spectrometer created at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) and irradiated with a 40-GeV beam of negatively charged pions from U-70 accelerator at the Institute for High Energy Physics (IHEP, Serpukhov). The use of a neutral trigger in the experiment being reported made it possible to suppress both charged particles and photons. The statistical confidence of the observer maximum is better than 6 standard deviation. The mass and width of the observed meson are M=1453±4 MeV and Г=13±5 MeV, respectively. Seeing its very narrow width this resonance is likely to be exotic meson.
|
Strong Interactions |
|
fadeeva@itep.ru |
| 316 |
The ATLAS Liquid Argon Calorimeter Group. |
The ATLAS Liquid Argon Calorimeter: Construction, Integration and Commissioning. |
The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end-caps with electromagnetic, hadronic and forward calorimeters. The liquid argon sampling technique, with an accordion geometry was chosen for the barrel electromagnetic calorimeter (EMB) and adapted to the end-cap (EMEC). The hadronic end-cap calorimeter (HEC) is using a copper-liquid argon sampling technique with flat plate geometry and is subdivided into two wheels in depth per end-cap. Finally, the forward calorimeter (FCAL) is composed of three modules featuring cylindrical electrodes with thin liquid argon gaps. The construction of the full calorimeter system is completed since mid-2004. Production modules constructed in institutes were assembled at CERN in 2003-2004 and inserted into the barrel and end-cap cryostats. The integration into the three cryostats was finished in 2004. Each of the cryostats was then cooled down to 87 K, filled with LAr and cold tested on the surface before its installation in the ATLAS underground cavern. Besides functional tests of the read-out electronics, the calibration system and the HV lines, measurements of capacitance, inductance and resistance of each of the 180.000 calorimeter cells as well as reflectrometry tests have been performed. Results from this cold commissioning on the surface will be presented demonstrating the excellent condition of the ATLAS LAr calorimeter system after its integration into cryostats, with more than 99,9% of the system working according to requirements.
The last of the three cryostats was installed inside the ATLAS hadronic tile calorimeter wheels in the ATLAS underground cavern in April 2006. Since then the electronics read-out system has been installed and tested. In the presentation the status of the electronics installation will be discussed and test results will be shown. Electronics calibration
is recorded in all calorimeters using the final ATLAS readout. Online software and monitoring tools have been developed as well as offline signal reconstruction. The signal reconstruction is one of the key points of the uniformity of the calorimeter response. The performance of the whole electronics chain (noise, stability, linearity etc) will be presented. The barrel cryostat is since autumn 2006 filled with LAr and one of the end cap cryostats has recently been filled. In order to verify the quality of the reconstruction methods, cosmic muon data has been recorded together with the hadronic Tile calorimeter. First results of this combined cosmic muon run inside the ATLAS cavern will be presented. |
Detectors and Data Handling |
"Abstract submitted by the LARG conference committee, speaker to be nominated later. Contacts: lund@particle.kth.se, martin.aleksa@cern.ch, hma@bnl.gov" |
lund@particle.kth.se |
| 317 |
Carmine Pagliarone, Arturo Fernandez-Tellez |
Cosmic Ray Physics with ACORDE at LHC |
ACORDE, the ALICE COsmic Ray DEtector is one of the ALICE detectors, presently under construction at LHC.
It consists of an array of plastic
scintillator counters placed on the three upper faces of the ALICE magnet. This array will act as Level 0 cosmic ray trigger and, together with other ALICE sub-detectors, will provide precise
information on cosmic rays with primary energies around $10^{15-17}$ eV. In this paper we will describe the ACORDE detector, trigger
design and electronics focusing on the Cosmic Ray physics program that it will be possible to explore both with ACORDE both with an extended Cosmic Rays array at LHC. |
Astroparticle Physics, Gravitational Waves and Cosmology |
It concern also Detectors and Data Handling. |
pagliarone@fnal.gov |
| 318 |
The ATLAS Liquid Argon Calorimeter Group |
Results from the ATLAS Combined Test Beams |
Beam tests of combinations of ATLAS calorimeters have been performed both for the barrel and end cap parts.
During a combined test beam in summer 2004 a slice of the ATLAS barrel detector - including all detector sub systems from the inner tracker, the calorimetry to the muon system - was exposed to particle beams (electrons, pions, photons, muons) with different energies (1GeV to 350GeV). The aim was to study the combined performance of the different detector sub systems in ATLAS-like conditions. We will present the electronics calibration scheme of the electromagnetic calorimeter and its implementation. The following studies on the combined testbeam data have been performed and will be presented: performance of the electromagnetic calorimetry down to very low energies (> GeV), photon reconstruction including converted photons and position measurements using the very precise ATLAS tracker and the electromagnetic calorimeter. These measurements have been compared to Monte Carlo simulations showing the good description of the data.
An end cap segment of the electromagnetic, hadronic and forward liquid argon calorimeters of ATLAS has been exposed to electron, pion and muon beams in the energy range from 10 to 200 GeV. The goal of this beamtest carried out at the CERN SPS is to obtain the calibration for the ATLAS calorimeter in a particular difficult transition region (2.4
| Detectors and Data Handling |
"Abstract submitted by the LARG conference committee, speaker to be nominated later. Contacts: lund@particle.kth.se, martin.aleksa@cern.ch, hma@bnl.gov " |
Bengt.Lund-Jensen@cern.ch |
|
| 319 |
Frank Simon (for the STAR collaboration) |
The STAR Tracking Upgrade Program |
The STAR collaboration is preparing a challenging tracking detector upgrade program using novel detector concepts. The purpose of the tracking upgrade is to investigate fundamental properties of the new state of strongly interacting matter produced in relativistic-heavy ion collisions at RHIC and to provide fundamental studies of the nucleon spin structure and dynamics in polarized proton-proton collisions at both 200 GeV and 500 GeV at RHIC.
At mid-rapidity, |y|<=1.2, the upgrade is the combination of active pixel sensors close to the collision point and silicon strip technology further outward while in the forward rapidity, 1.0 < y < 2.0, a system of six triple-GEM disks using Tech-Etch produced GEM foils is currently under development.
We will report on the current status of the design efforts and on results from the technology development.
|
Detectors and Data Handling |
|
fsimon@mit.edu |
| 320 |
A. Hoecker, J. Stelzer, F. Tegenfeldt, H. Voss |
TMVA - Multivariate Data Mining in Physics Analysis |
In high-energy physics, with the search for ever smaller signals in
ever larger data sets, it has become essential to extract a maximum of
the available information from the data. Multivariate classification
methods based on machine learning techniques have become a fundamental
ingredient to most analyses. Also the multivariate classifiers
themselves have significantly evolved in recent years. Statisticians
have found new ways to tune and to combine classifiers to further gain
in performance. Integrated into the analysis framework ROOT, TMVA is
a toolkit which holds a large variety of multivariate classification
algorithms. They range from rectangular cut optimization using a
genetic algorithm and from likelihood estimators, over linear
discriminants and non-linear neural networks, to sophisticated more
recent classifiers such as boosted decision trees, rule ensemble fitting
and a support vector machine. TMVA manages the simultaneous training,
testing, and performance evaluation of all these classifiers with a
user-friendly interface, and expedites the application of the trained
classifiers to data.
|
Detectors and Data Handling |
|
andreas.hoecker@cern.ch |
| 321 |
Silvia Pascoli |
Leptogenesis and low energy CP-violation |
It was commonly thought that the observation of low energy leptonic CP-violating phases would not automatically imply the existence of a baryon asymmetry in the leptogenesis scenario. This conclusion does not generically hold when the issue of flavour is relevant and properly taken into account in leptogenesis. I will illustrate this point from the theoretical point of view and with examples. |
Neutrino Physics |
|
silvia.pascoli@durham.ac.uk |
| 322 |
Jon M. Butterworth, John R. Ellis, Are R. Raklev |
Reconstructing Sparticle Mass Spectra using Hadronic Decays |
Most sparticle decay cascades envisaged at the Large Hadron Collider (LHC) involve hadronic decays of intermediate particles. We use state-of-the art techniques based on the \kt jet algorithm to reconstruct the resulting hadronic final states for simulated LHC events in a number of benchmark supersymmetric scenarios. In particular, we show that a general method of selecting preferentially boosted massive particles such as W, Z or Higgs bosons decaying to jets, using sub-jets found by the \kt algorithm, suppresses QCD backgrounds and thereby enhances the observability of signals that would otherwise be indistinct. Consequently, measurements of the supersymmetric mass spectrum at the per-cent level can be obtained from cascades including the hadronic decays of such massive intermediate bosons. |
Physics Beyond the Standard Model |
See arXiv:hep-ph/0702150 |
Are.Raklev@cern.ch |
| 323 |
Sergio Palomares-Ruiz |
TeV gamma-rays and neutrinos from photodissociation of cosmic-ray nuclei in Cygnus OB2 |
It is commonly assumed that high-energy gamma-rays are made via either purely electromagnetic processes or the hadronic process of pion production, followed by decay. We investigate astrophysical contexts where a third process may dominate, namely the photodissociation of highly boosted nuclei followed by daughter de-excitation. This process is proposed as a candidate explanation of the recently discovered HEGRA source at the edge of the Cygnus OB2 association. The Lyman-alpha background is provided by the rich O and B stellar environment. It is found that (1) the HEGRA flux can be obtained if there is efficient acceleration at the source of lower energy nuclei; (2) a strong suppression of the gamma-ray spectrum compared to an Egamma^{-2} behavior is predicted at energies ~ 1 TeV (some of these energies will be probed by the upcoming GLAST mission); (3) a TeV neutrino counterpart from neutron decay following helium photo-disintegration will be observed at IceCube only if a major proportion of the kinetic energy budget of the Cygnus OB2 association is expended in accelerating nuclei. This mechanism offers an important contribution to gamma-ray astronomy in the era of intense observational activity. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
sergio.palomares-ruiz@durham.ac.uk |
| 324 |
heLiCal Collaboration |
Spin tracking at the ILC |
Polarized electron and positron beams are foreseen for the
future International Linear Collider (ILC), with polarized electrons
already included in the baseline design and polarized positrons seen as
a highly-desirable upgrade. High precision physics requires the
polarization of both beams to be known with a relative uncertainty of
approximately 0.5% or better. Therefore all possible depolarization
effects that could operate between the polarized sources and the
interaction regions have to be carefully modelled. The "heLiCal"
collaboration aims to provide a full "cradle-to-grave" analysis of all
depolarization effects at the ILC, and to develop software tools to
carry out appropriate computer simulations. In this paper we report on
the first phase of our work which includes extensive simulations of the
ILC spin-dynamics and a detailed study of beam-beam depolarization
effects at the interaction point(s). |
Accelerator RD and Technology |
|
g.a.moortgat-pick@durham.ac.uk |
| 325 |
heLiCal Collaboration |
Polarised positron source at the ILC |
The positron source for the International Linear Collider is a helical
undulator-based design, which can generate unprecedented quantities of
polarised positrons. The heLiCal collaboration takes responsibility for
the design and prototyping of the superconducting helical undulator, which
is a highly demanding short period device with very small aperture, and
also leads the start to end simulations of the polarised electrons and
positrons to ensure that the high polarisation levels generated survive
from the source up to the collision point. This paper will provide an
update on the work of the collaboration, focusing on these two topic
areas, and will also discuss future plans.
|
Accelerator RD and Technology |
|
g.a.moortgat-pick@durham.ac.uk |
| 326 |
E166 Collaboration |
Undulator-based production of polarized positrons |
In the baseline design for the ILC, the undulator-based scheme
is used as positron source. Such scheme has excellent prospects
to achieve the high luminosity demands. In addition
it opens an easy path to provide even polarized positrons which
is important for the physics program at the ILC.
The E166 experiment has tested this scheme in the FFTB at
Slac. The experiment was carried out
with a one meter long, short-period, pulsed helical undulator.
A low emittance 46.6 GeV electron beam passing through this
undulator generated circularly polarized photons with energies
in the range of 8 MeV. They were converted in a relatively thin
target to generate longitudinally polarized positrons. The
resulting positron polarization has been measured at different
energies of positrons and is in agreement with the
expectations.
|
Accelerator RD and Technology |
|
g.a.moortgat-pick@durham.ac.uk |
| 327 |
The CKMFitter Group |
The CKM Matrix Global Fit and A model-independent analysis of New Physics contributions in $\Delta F=2$ transi |
An up-to-date profile of the Cabibbo-Kobayashi-Maskawa matrix will be given, with emphasis on the interpretation of recent results on CP violation from the B factories and recent measurements in B physics from the Tevatron. We will review the relevant experimental and theoretical inputs to the CKM matrix global fit and give numerical and graphical constraints on the CKM parameters. Predictions of related physical observables will also be presented.
The Standard Model (SM) describes with a great success so far, the data in the flavor sector. It is hence important to quantitatively explore how far the present experiments are constraining potential New Physics (NP) contributions. The NP effects in the $B^0-\bar B^0$ mixing amplitude can be model-independently accounted for by introducing only two parameters. The constraints on these parameters issued from the most recent $B$ transition data will be presented. |
Flavour Physics and CP Violation |
|
Stephane.Monteil@in2p3.fr |
| 328 |
Gudrid Moortgat-Pick |
The role of polarized positrons and electrons in revealing fundamental interactions at the linear collider |
The proposed International Linear Collider (ILC)
is well-suited for discovering physics
beyond the Standard Model and for precisely
unraveling the structure of the
underlying physics.
The physics return can be maximized by
the use of polarized beams.
This report shows the paramount role of polarized beams and
summarizes the benefits obtained from
polarizing the positron beam, as well as the electron beam. The
physics case for this option is illustrated explicitly by
analyzing reference reactions in different physics scenarios. The
results show that positron polarization, combined with the clean
experimental environment provided by the linear collider, allows to
improve strongly the potential of searches for new particles and
the identification of their dynamics, which opens the road
to resolve shortcomings of the Standard Model.
|
Physics Beyond the Standard Model |
|
g.a.moortgat-pick@durham.ac.uk |
| 329 |
Gudrid Moortgat-Pick |
Combined LHC/ILC analysis of a SUSY scenario with heavy sfermions |
We discuss the potential of
analyses at the Large Hadron Collider
and the planned International Linear Collider to explore low-energy
supersymmetry in a difficult region of the parameter space characterized by
masses of the scalar SUSY particles around 2~TeV. Precision
analyses of cross sections for light chargino production and
forward--backward
asymmetries of decay leptons and hadrons at the ILC with sqrt{s}=500~GeV,
together with mass information on tilde{chi}^0_2 and squarks from
the LHC,
allow us to determine the underlying fundamental gaugino/higgsino MSSM
parameters, to constrain the masses of the heavy, kinematically
inaccessible sparticles and to outline the needed higher energy scale for the second stage of the ILC. No assumptions on a specific SUSY-breaking mechanism are imposed. |
Physics Beyond the Standard Model |
|
g.a.moortgat-pick@durham.ac.uk |
| 330 |
Gudrid Moortgat-Pick |
Triple product correlations for revealing CP-violating effects in supersymmetric processes at LHC and ILC |
CP-violating effects in production and decay of supersymmetric particles are
studied. The CP sensitive asymmetries by means of triple product
correlations are exploited and their dependence on the complex parameters
M_1 and \mu are analysed.
Numerical predictions for the asymmetries and their measurability at the
LHC and the future International Linear Collider are given. Our results show that the CP asymmetries can be measured with good statistical significances in a large region of the parameter space of the Minimal Supersymmetric Standard Model.
|
Physics Beyond the Standard Model |
|
g.a.moortgat-pick@durham.ac.uk |
| 331 |
Veronique Boisvert, Kevin McFarland, Veronica Sorin, Kirsten Tollefson, Zeynep Gunay Unalan, Yen-Chu Chen, Andy Beretvas, Jaroslav Antos, Stanislav Tokar , Peter Bednar |
CDF top charge measurement |
Since top quark's discovery in 1995, there have been several measurements of the top quark's mass and cross section. Due to this quark's
special role in electroweak symmetry breaking, other parameters such as its charge and spin should also be measured. We present the first
CDF measurement of the top quark's charge using its decay products from a sample of 1.2 fb$^{-1}$ of data collected with the CDFII
detector at the Tevatron collider at Fermilab. The standard model predicts the top quark charge to be +2/3 but alternative theories allow
a fourth generation exotic quark with a charge of -4/3. We classify events as either top-like or exotic-like depending on the the charge
of the b jet and of the associated W boson. We report confidence level limits for the data to exclude the exotic or standard model
hypothesis. |
High-Energy Electroweak Physics |
|
pbednar@fnal.gov |
| 332 |
H. Fraas, F. Franke, S. Hesselbach, G. Moortgat-Pick |
Distinguishing between MSSM and NMSSM by combined LHC and ILC
analyses |
We show that the interplay between the LHC and the ILC with sqrt{s}=500 GeV
might be crucial for the discrimination between the minimal and next-to-minimal
supersymmetric standard model. We present a NMSSM scenario that cannot be distinguished from the MSSM by cross sections and mass measurements if only the light neutralinos and the lightest chargino are kinematically accessible, even if one of the neutralinos has a significant singlino component. Mass predictions for the heavier neutralinos from the ILC analysis and their observation at the LHC lead to an identification of the neutralino mixing character and the underlying supersymmetric model in a combined LHC/ILC analysis. In our numerical example we include uncertainties in the mass measurements and use standard methods of supersymmetric parameter determination.
|
Physics Beyond the Standard Model |
|
g.a.moortgat-pick@durham.ac.uk |
| 333 |
CLEO Collaboration |
Dipion transitions in bottomonium at CLEO |
The CLEO experiment has collected roughly 6 million Y(3S) and
9 million Y(2S) decays. We report results from studies of both
charged and neutral two-pion transitions:
Y(3S) --> Y(2S) pi pi,
Y(3S) --> Y(1S) pi pi and
Y(2S) --> Y(1S) pi pi, with both exclusive and inclusive decays
of the final state Upsilon.
Using the two-dimensional space of two-pion invariant mass and
pion decay angle, we report branching ratios for these transitions,
and determinations of their decay matrix elements.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 334 |
CLEO Collaboration |
Experimental Studies of rare transitions and decays in the Upsilon family at CLEO |
The CLEO III detector has accumulated a sample of about 9 million Upsilon(2S) and 6 million Upsilon(3S) decays.
These can undergo electric dipole transitions to the triplet-P states chi(b) and chi'(b), and suppressed magnetic dipole transitions to the singlet-S state eta(b), which has never been observed. Exclusive decays of the
chi(b) and chi'(b) states are examined with the aim of sharpening searches for the eta(b).
The same data are also examined for evidence for the hadronic transitions
Upsilon(2S) -> eta Upsilon(1S) and
Upsilon(3S) --> eta Upsilon(1S), using decays eta -> gamma gamma, eta -> pi+ pi- pi0,
and eta -> pi+ pi- gamma, and identifying
the Upsilon(1S) by its decay into
e+ e- or mu+ mu-.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 335 |
CLEO Collaboration |
Exclusive radiative Upsilon decays at CLEO |
We report on the study of exclusive radiative decays of the
Upsilon(1S) resonance into the all neutral final states gamma-pi0pi0,
gamma-pi0eta, gamma-etaeta, gamma-eta and gamma-etaprime, using
1.13 fb-1 of e+e- annihilation data taken with the CLEO III detector
operating at the Cornell Electron Storage Ring. In the gamma-pi0pi0
channel we measure the branching ration for the mode
Upsilon(1S) -> gamma f_2(1270) to be (10.5+-1.6+1.9-1.8) x 10^-5.
We find no significant signals in the other modes, and place upper
limits on them. Our upper limits on exclusive radiative decays to
eta and etaprime provide discrimination between models of radiative
decays of charmonia.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 336 |
CLEO Collaboration |
Search for the 1S_0 (eta_b) ground state of bottomonium at CLEO |
A search for the long missing eta_b(1S) ground state of the bottomonium
system is being made at CLEO using the 21 million Upsilon (1S) produced
in e+e- annihilations at CESR. The reaction studied is
Upsilon(1S) -> gamma eta_b, eta_b -> hadrons. Events with hadron
multiplicities of 4, 6, 8, and 10 are identified. Preliminary results
will be presented.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 337 |
CLEO Collaboration |
Studies of fragmentation and particle yields in the Upsilon family at CLEO |
The CLEO III detector has accumulated a sample of about 21 million Upsilon(1S),
9 million Upsilon(2S) and 6 million Upsilon(3S) decays. We present final
results on a variety of fragmentation and decay analyses:
(i) open charm production in both Upsilon(nS) and chi_b decays;
(ii) comparisons of qqbar and gg fragmentation to heavy mesons and baryons,
both from comparison of radiative Upsilon(nS) decays to ISR continuum events
and from comparison of chi_b1 or chi_b2 decays to those of chi_b1;
(iii) limits on narrow resonance production in radiative Upsilon(nS) decays
over a wide range of masses; and
(iv) the yield of anti-deuterons in Upsilon(1S) decays.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 338 |
CLEO Collaboration |
Search for invisible and lepton flavor violating decays of Upsilon at CLEO |
Using more than 1 fb-1 data collected on each of the Upsilon(1S,2S,3S)
resonances, CLEO made two searches for new physics scenarios beyond
the Standard Model: (i) for Upsilon(1S) resonance decays to weakly
interacting particles which cannot be observed in the detector
(as a possible indication of coupling between the Standard Model and
the dark matter sector); (ii) sfor lepton flavor violating (LFV) decay
Upsilon(1S,2S,3S) -> mu+ tau-.
The measurement of invisible decay of the Upsilon(1S) was performed using
the Upsilon(2S) -> pi+ pi- Upsilon(1S) transition and inferring the presence
of the Y(1S) from the missing mass recoiling against the pi+pi- in the event.
After taking backgrounds into account, no significant signal is observed
and a 90% C.L. upper limit B[Upsilon(1S) -> invisible] < 0.39% is obtained.
In the LFV analysis, we identify the tau through its electron decay and
utilize multi-dimensional likelihood fitting with PDF shapes determined
from independent data samples. We present 95%CL upper limits on LFV branching
fractions of the Upsilons and interpret our results in terms of an exclusion
plot on energy scale and coupling of a BSM interaction in the framework of
effective field theory.
|
Physics Beyond the Standard Model |
|
cleoac@mail.lepp.cornell.edu |
| 339 |
CLEO Collaboration |
chicJ properties at CLEO (group abstract) |
Using 26 Million psi(2S) decays we will present improved chi_c
measured widths and also present measured branching
fractions of chic to various final states, including
two pseudoscalar mesons, two vectors, and baryon-antibaryon pairs.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 340 |
CLEO Collaboration |
eta_c(1S) and eta_c(2S) analyses at CLEO (group abstract) |
Based on the 26 million psi(2S) decays collected
with the CLEO-c detector, we present preliminary results
of analyses investigating eta_c and eta_c(2S) properties.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 341 |
CLEO Collaboration |
Study of h_c decays at CLEO (group abstract) |
Recently CLEO reported the identification of the elusive 1P1 (h_c)
state of charmonium via a study of the reaction
psi' -> pi0 h_c, h_c -> gamma eta_c. The then available data for
3 million psi' were used to obtain resonance parameters whose precision
was limited by statistics. Additional data were recently taken by CLEO-c,
and a total sample of 26 million psi' have now been analyzed.
Preliminary results of the above reaction
as well as hadronic decays of h_c will be presented.
|
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 342 |
CLEO Collaboration |
A Precision Determination of D0 Mass at CLEO |
A precision measurement of the D0 meson mass has been made using 281 pb-1
of e+e- annihilation data taken with the CLEO-c detector at the
psi(3770) resonance. The exclusive decay D0 -> K0Sphi has been used to
obtain M(D0) = 1864.847 +- 0.150 (stat.) +- 0.095 (syst.) MeV. This
corresponds to M(D0D*0bar) = 3871.81 +- 0.36 MeV and leads to a
well-constrained determination of the binding energy of the proposed
|D0D*0bar> molecule X(3872), as E_b = 0.6 +- 0.6 MeV.
|
Strong Interactions |
This may also be of interest to the Flavor Physics section. |
cleoac@mail.lepp.cornell.edu |
| 343 |
CLEO Collaboration |
Absolute D(s) Hadronic Branching Fraction Measurements at CLEO |
Measurements of the absolute branching fractions of D mesons to
reference hadronic final states normalize many measurements in charm and
bottom physics. Using large samples of D0 D0bar, D+ D-, and Ds Ds*
events collected by the CLEO-c experiment at the CESR e+ e- collider, we
obtain precise measurements of the branching fractions of key decay
modes, including D0->K pi, D+ -> K pi pi, and Ds+ -> K K pi.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 344 |
CLEO Collaboration |
Decays of D mesons to final states containing eta and etaprime at CLEO |
We present new measurements of singly and doubly Cabibbo-suppressed
decays of $D$ mesons into final states containing eta and etaprime
mesons from CLEO-c. The study of these final states provides
additional information on SU(3) symmetry breaking and final state
interaction effects in D meson decays.
We also present inclusive branching fractions D,Ds --> eta/eta'/phi + X.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 345 |
CLEO Collaboration |
Comparison of D --> K0SPi and D --> K0LPi Decay Rates at CLEO |
We present measurements of D --> K0_S pi and D --> K0_L pi
branching fractions using 281 pb^{-1} of psi(3770) data at the
CLEO-c experiment. We find that BF(D0 --> Kspi0) is larger than
BF(D0 --> Klpi0), and for
BF(D^+ --> Kspi^+) and BF(D^+ --> Klpi^+) we observe no
measurable difference. The asymmetry in the
D0 branching fractions is consistent with the value based on
the U-spin prediction
A(D0 --> K0 pi0)/A(D0 --> bar K0 pi0) = -tan2 theta_C,
where theta_C is the Cabibbo angle.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 346 |
CLEO Collaboration |
Search for CP Violation in the D+- -> K+K- pi+- Dalitz Plot at CLEO |
We report on a search for a CP asymmetry in the singly
Cabibbo-suppressed decay D+ -> K+ K- pi+ using a data sample of 281 pb-1
accumulated with the CLEO-c detector on the psi(3770) resonance. We have
searched for CP asymmetries in a Dalizt plot based analysis that also
determines the amplitudes and relative phases of the intermediate states.
Furthermore, limits are obtained from specific mass interval.
The CP asymmetries are measured to be consistent with zero.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 347 |
CLEO Collaboration |
Constraining gamma/phi_3 with a Model-Independent Dalitz Plot Analysis of CP-Tagged and Flavor-Tagged D->K0Spi+pi- and K0Lpi+pi- at CLEO |
Precision determination of the CKM angle \gamma/\phi_3 depends upon
constraints on charm mixing amplitudes, measurements of doubly-Cabibbo
suppressed amplitudes and relative phases, and studies of charm Dalitz
plots tagged by flavor or CP eigenstates. We describe the selection
criteria for the tagged KSpipi and KLpipi samples, the technique to
constrain the Dalitz model uncertainty, and the CLEO-c impact on
\gamma/\phi_3 measurements at B-factories.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 348 |
CLEO Collaboration |
Study of Charm Mixing and Strong Phases Using Quantum Correlations at CLEO |
We exploit the quantum coherence between pair-produced D0 and D0bar in
psi(3770) decays to study charm mixing and to make a first measurement
of the relative strong phase delta between D0 to K- pi+ and
D0bar to K- pi+. Using 281 pb^-1 collected with the
CLEO-c detector at E_cm = 3773 MeV, we measure y * cos delta, and
we perform an average with other available measurements.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 349 |
CLEO Collaboration |
Dalitz analyses of the D+ --> pi- pi+ pi+ and D+ --> K- pi+ pi+ decays |
Using 0.78M e+e- --> psi(3770) --> D+ D- events produced by the
Cornell Electron Staorage Ring (CESR) and observed by the CLEO-c detector,
we perform a Dalitz plot analysis of D+ --> pi- pi+ pi+ and
D+ --> K- pi+ pi+ decays. Due to the different sizes of the event
sample, 7K and 67K, and background fractions, 30% and 1%, respectively,
we apply different strategy in these two analyses. For the
D+ --> pi- pi+ pi+ decay we use an isobar model with three
alternative models of the pi- pi+ S-wave parameterization.
For the D+ --> K- pi+ pi+$ decay, a quasi-model-independent approach is
used. We present results on the model parameters and the fit fractions
of intermediate states. Our results confirm the conclusions of the previous
high statistics experiments, E791 and FOCUS, on the dominant contribution of
the low-mass (pi- pi+) and (K- pi+) S-waves in these decays.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 350 |
CLEO Collaboration |
Suppressed and Forbidden Decays of Ds+ Mesons to Two Pseudoscalar Mesons at CLEO |
Using the data collected near the Ds*+ Ds- peak production
energy by the CLEO-c detector we study the decays of Ds+ mesons to two
pseudoscalar mesons. We report searches for the singly-Cabibbo-suppressed
Ds+ decay modes K+ eta, K+ eta', pi+ K0S, K+ pi0,
and the forbidden decay mode Ds+ --> pi+ pi0.
We normalize against the Cabibbo-favored Ds+ modes, pi+ eta,
pi+ eta', and K+ K0_S.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 351 |
CLEO Collaboration |
Hadronic cross-sections around 4GeV as well as between 7 and 10 GeV at CLEO |
Using the CLEO-c detector at the CESR storage ring, we have measured
inclusive and exclusive cross sections for the production of D+, D0 and
Ds+ mesons in e-e- annihilations at thirteen center-of-mass energies
between 3.97 and 4.26 GeV. Exclusive cross sections are presented for
final states consisting of two charmed mesons (D Dbar, D* Dbar,
D* D*bar, Ds+ Ds-, Ds*+ Ds-, and Ds*+ Ds*-), and for ``multi-body''
processes in which the charmed mesons are accompanied by a pion.
No enhancement in any final state is observed at the energy of the
recently discovered Y(4260).
We complement this analysis with a measurement of R at 7-10GeV. |
Strong Interactions |
|
cleoac@mail.lepp.cornell.edu |
| 352 |
CLEO Collaboration |
Measurement of B(Ds+ --> ell+nu) and B(D+ --> ell+nu) and the Decay Constants f_Ds+ and f_D+ |
Using the decays D --> mu nu and Ds --> mu(tau) nu and the CLEO-c
detector, we have made incisive measurements of the decay constants
f_D and f_Ds . These are prime tests of QCD calculations related to
heavy quark decays. We examine e+e- --> Ds-Ds{*+} and
Ds*- Ds+ interactions at 4170 MeV in order to
measure the decay constant f_Ds+. We use the Ds+ --> ell+nu channel,
where the ell+ designates either a mu+ or a tau+, when the
tau+ --> pi+ nubar. We also examine D Dbar pairs produced at a center
of mass energy of 3770 MeV in order to study D to mu nu.
|
Flavour Physics and CP Violation |
This abstract may be of interest to the Electroweak Physics session also. |
cleoac@mail.lepp.cornell.edu |
| 353 |
CLEO Collaboration |
D --> pi/K e nu at CLEO |
Using a 281 pb^{-1} data sample collected with the CLEO-c
detector at the psi(3770) resonance, we study the decay
D --> pi,K e nu. We pursue two avenues:
(1) We identify events where one D meson has decayed to a hadronic
final state and the other D meson has decayed to a semileptonic final state,
(2) we reconstruct the neutrino 4-vector via the missing energy and
momentum in the event, making use of the hermeticity of the detector,
but do not impose any requirements on the decay of the second D.
We present measurements of the absolute semileptonic branching ratios
and differential decay rates for D --> K e nu_e and D --> pi e nu_e.
The decay rates are fit to several form factors models and results are
compared to theory. Using |V_{cq}| obtained from the unitarity
constraints of the CKM matrix, form factors f_+(q2) are measured
and used to test unquenched LQCD predictions. Using LQCD calculations
of f_+(0), we present direct measurements of V_{cs} and V_{cd}.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 354 |
CLEO Collaboration |
D --> vector l nu form factors at CLEO |
Using a 281/pb data sample collected with the CLEO-c detector
at the psi(3770) resonance, we present improved measurements
of absolute branching fractions in the semileptonic decays
D0 --> rho- e+ nu_e and D+ --> rho0 e+ nu_e.
By performing a four-dimensional maximum likelihood fit
to the distribution of kinematic variables, we have measured,
for the first time, the semileptonic form factor ratios R_V and R_2
in D0 --> rho- e+ nu_e and D+ --> rho0 e+ nu_e.
Using our measurements of absolute branching fractions and form factor
ratios, world averages for D0 and D+ lifetimes and the value of
V_{rm cd} obtained from the CKM matrix unitarity constraints,
we determine absolute normalizations of form factors A_1(0), A_2(0)
and V(0).
Model-independent form factor measurements by CLEO of the vector
final state D --> K* e nu are already published.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 355 |
CLEO Collaboration |
Rare D semileptonic modes at CLEO |
Using a 281/pb data sample collected at the psi(3770) resonance
with the CLEO-c detector, we present results of searches for rare
semileptonic D meson decays.
Our results include the first observation and an absolute branching
fraction measurement of D+ --> eta e+ nu_e,
evidence for and absolute branching fraction measurement of
D0 --> K- pi+ pi- e+ nu_e,
and upper limits for D+ --> etaprime e+ nu_e and
D+ --> phi e+ nu_e which are about two orders of magnitude
more restrictive than those obtained by other experiments to date.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 356 |
Anna Sfyrla (CDF Collaboration) |
WW and WZ production in charged lepton-neutrino plus dijet final state at CDF |
We present a search for WW and WZ production in charged lepton-neutrino plus dijet final states at $\sqrt{s}=1.96$~TeV, using approximately 1.3 fb$^{-1}$ of data accumulated with the CDF detector. This channel has not been observed in hadron colliders so far because of the large single W plus jets background. This mode however has much larger branching fractions than the cleaner fully leptonic mode making it more sensitive to anomalous triple gauge couplings which would manifest themselves at higher transverse W momenta. Because the final state is topologically similar to the associated production of a Higgs with a W, the techniques developed in this analysis will also be applicable there. The analysis is optimized by using an artificial neural network for the event selection. |
High-Energy Electroweak Physics |
|
sfyrla@fnal.gov |
| 357 |
CLEO Collaboration |
Ds semileptonic decays at CLEO |
We present studies of semileptonic decays of the Ds meson.
This includes several first measurements of absolute Ds
semileptonic decays, of inclusive branching fractions as well as
exclusive Cabibbo favored and Cabibbo suppressed decay modes.
|
Flavour Physics and CP Violation |
|
cleoac@mail.lepp.cornell.edu |
| 358 |
K.K. Gan |
Bandwidths of micro twisted-pair cables and fusion spliced SIMM-GRIN fiber and radiation hardness of PIN/VCSEL arrays |
We study the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel optical link architecture. The electrical signals between the current pixel modules and the optical modules are transmitted via micro-twisted cables. The optical signals between the optical modules and the data acquisition system are transmitted via rad-hard SIMM fibers spliced to rad-tolerant GRIN fibers. The link has several nice features. We have measured the bandwidths of the transmission lines and the results indicate that the micro twisted-pair cables can transmit signals up to ~ 1 Gb/s and the fusion spliced fiber ribbon can transmit signals up to ~ 2 Gb/s. We have irradiated PIN and VCSEL arrays with 24 GeV protons and find at least one candidate PIN and one VCSEL array that can survive to the SLHC dosage. |
Detectors and Data Handling |
Speaker to be determined |
gan@mps.ohio-state.edu |
| 359 |
K.K. Gan |
An MT-Style Optical Package for Optical Data Transmission |
An novel optical package for mounting a VCSEL or PIN array for transmitting and receiving optical signals has been developed. The package is fabricated using BeO as the substrate for efficient removal of heat produced by the array. The array is connected to the driver or receiver chip using three dimenional traces together with wire bonds. Each array couples to a fiber ribbon terminated in a commercial MT connector. The package is quite compact with its physical size significantly smaller than that of the MT connector. This design simplifies the testing and assembly of the optical components because the MT connector with the long fibers attached can be remounted with ease while preserving good light coupling efficiency. This non-magnetic package can be used in the high radiation environment such as the SLHC. |
Detectors and Data Handling |
Speaker to be determined |
gan@mps.ohio-state.edu |
| 360 |
Kenneth Lessnoff |
Carbon fibre spherical mirrors for the LHCb RICH1 detector |
The design, manufacture and testing of light-weight carbon fibre spherical converging mirrors for the upstream Ring Imaging Cherenkov Detector of LHCb, RICH1, is described. The mirrors need to be light-weight to reduce the material budget, fluorocarbon-compatible to avoid degradation in the RICH1 C4F10 radiator, and be able to withstand the intense radiation environment of the LHC. The results for prototypes and for the final mirrors are reported. |
Detectors and Data Handling |
|
kenneth.lessnoff@cern.ch |
| 361 |
ZEUS Collaboration |
Leading proton production in deep inelastic ep scattering with ZEUS at HERA |
The semi-inclusive reaction ep -> eXp, with a final-state proton carrying
a large fraction of the incoming proton energy, xL > 0.4, and transverse
momentum squared pT2 < 0.5 GeV2, was studied with the ZEUS detector at
HERA for exchanged photon virtualities Q2 > 3 GeV2 using an integrated
luminosity of 12.8 pb-1. Leading protons were detected with the ZEUS
leading proton spectrometer. The leading-proton production cross
section, its ratio to the inclusive DIS ep cross section and the leading
proton structure function F2LP were measured as a function of xL, pT2, Q2
and the Bjorken scaling variable, x. The mean charge multiplicities were
measured as a function of the total hadronic momentum and compared to e+e-
and pp data.
|
Strong Interactions |
|
halina@mail.desy.de |
| 362 |
M. Bonesini on behalf of NA56/SPY Collaboration |
Deuteron production in p-Be interactions at 450 GeV/c and the coalescing model |
The analysis of the deuteron production in the NA56/SPY data, taken with 450 GeV/c protons on a Beryllium target is summarized. Results include an evaluation of the cross-section production ratios (d/p) and of the deuteron invariant cross sections, both as a function of momentum in the forward direction and of transverse secondary momentum.
In the framework of the coalescence model for deuteron production the coalescence factor k is determined, with no evidence for a p_d^-2 dependence, as assumed in some theoretical models. |
High-Energy Nuclear Physics |
also suitable for Strong Interactions Section |
maurizio.bonesini@mib.infn.it |
| 363 |
Antony Sarrat, CEA Saclay |
Micropattern based TPC for T2K's tracking system |
T2K is a second generation long baseline neutrino experiment designed to investigate theta_{13}. This measurement could be the key to understand the matter-antimatter asymmetry of the universe. The neutrino flux and cross sections will be measured in a near detector complex, located at 280m from the proton beam target. A major component of this magnetized near detector include 3 large TPCs which will provide an accurate measurement of the neutrino energy spectrum.
The total readout area of the TPCs (appr. 10m^2), will be instrumented with gaseous micro-pattern detectors, using the novel "bulk" Micromegas technology: a specific chip has been designed to read the 120k pads. Two large "bulk" detectors (26*27 cm^2) have been built and tested in the former HARP field cage at CERN, with cosmic ray data in a magnetic field up to 0.4T.
We present the major components of this innovative TPC detector, including the field cage, the Micromegas instrumented end-plate and the electronic readout system. The detector performances, extrapolated from prototype data, will also be presented. |
Detectors and Data Handling |
|
asarrat@cea.fr |
| 364 |
Rui Luo |
Leptogenesis in the E6SSM |
We investigate leptogenesis in the E6 inspired Supersymmetric Standard Model (E6SSM), which has an extra U(1) symmetry. In this model, the right-handed neutrino doesn't participate in gauge interactions, allowing it to be used for both the SEESAW mechanism and leptogenesis. The decay of this heavy right-handed Majorana neutrino, via exotic leptons and leptoquarks, leads to the generation of a lepton asymmetry. We find that the lepton asymmetry can be drastically enhanced, even when the right-handed neutrino is much lighter than 10^9 GeV . |
Neutrino Physics |
Funding for the conference is dependent on presentation of a talk. |
r.luo@physics.gla.ac.uk |
| 365 |
C.D.Froggatt, R.Nevzorov, H.B.Nielsen |
Smallness of the cosmological constant and the multiple point principle |
It is well known that global symmetries can protect a zero value for the cosmological constant in the N=1 supergravity (SUGRA).
The best motivated scenario of this type is no--scale supergravity where global symmetries guarantee not only vanishing of the vacuum energy
density but also preserve local supersymmetry (SUSY) in all vacua. The breakdown of these symmetries that ensures the vanishing of the
vacuum energy density near the physical vacuum leads to the natural realization of the multiple point principle (MPP) assumption, i.e.
results in the set of degenerate vacua with broken and unbroken local supersymmetry. We present the minimal SUGRA model where the MPP assumption is realised naturally at the tree--level. In this model vacua with broken
and unbroken local supersymmetry in the
hidden sector (first and second phases) have
the same energy density without any extra fine-tuning. Although hidden sector does not
give rise to the breakdown of supersymmetry in the second phase SUSY may be broken there dynamically in the observable sector. Then a positive value of the energy density in the second vacuum is induced which can be assigned, by virtue of MPP, to all other phases including
the one in which we live. The total vacuum
energy density is naturally tiny or zero in this case. In order to reproduce the observed value
of the cosmological constant and preserve gauge coupling unification the low energy matter content has to involve extra matter beyond
the MSSM contained in 5+\bar{5} representations of SU(5). Extra fields have masses of the order of supersymmetry breaking scale so that they can be detected at future colliders. We also discuss the supersymmetry breakdown and possible solution of the cosmological constant problem by MPP in
models with an enlarged gauge symmetry. |
Astroparticle Physics, Gravitational Waves and Cosmology |
"based on C.Froggatt, R.Nevzorov and H.B.Nielsen, On the smallness of the cosmological constant in SUGRA models, Nucl. Phys. B 743 (2006) 133; arXiv:hep-ph/0511259." |
r.nevzorov@physics.gla.ac.uk |
| 366 |
Peter Athron |
Electroweak symmetry breaking in the E6SSM |
The Exceptional Supersymmetric Standard Model (E6SSM) is an E6 inspired model with an extra gauged U(1) symmetry, which solves the mu-problem in a similar way to the NMSSM but without the accompanying problems of singlet tadpoles or domain walls. It predicts new exotic particles at the TeV scale. We investigate the Renormalisation Group Evolution of the MSUGRA inspired Constrained ESSM and test electroweak symmetry breaking for a selection of interesting scenarios. We present detailed particle spectra for these models that could be observed at the LHC. The two loop corrections to the light Higgs allow it to be as heavy as 155 GeV, which may ease the Little Hierarchy problem. |
Physics Beyond the Standard Model |
Please note that I will only get funding for the conference if I give a talk. |
p.athron@physics.gla.ac.uk |
| 367 |
H1 Collaboration |
Dijet Cross Sections and Parton Densities in Diffractive DIS at HERA |
Differential dijet cross sections in diffractive deep inelastic scattering
processes have been measured with the H1 detector at HERA using an
integrated luminosity of 51.5 pb^{-1}.
The selected events are of the type $ep\rightarrow eXY$, where
the system $X$ contains at least two jets
and is well separated in rapidity from the proton dissociation system $Y$.
The dijet data are compared with QCD predictions at next to leading
order (NLO) based on diffractive parton distribution functions (DPDFs)
extracted from measurements of inclusive diffractive deep inelastic scattering.
The prediction describes the dijet data well at low and intermediate $\zpom$
(the fraction of the exchanged momentum carried by the parton entering
the hard interaction) where the gluon density is well determined from
the inclusive diffractive data, supporting QCD factorisation.
A new set of diffractive parton densities is obtained through a simultaneous fit
to the inclusive diffractive data and the new dijet results.
This allows for a precise determination of both the diffractive quark and
gluon distributions in the range $0.05<\zpom<0.9$. In particular, the
precision on the gluon density at high momentum fractions is improved compared
to previous extractions. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 368 |
C.D.Froggatt, R.Nevzorov, H.B.Nielsen |
MPP inspired Two-Higgs Doublet Model |
Multiple point principle (MPP) postulates the existence of as many phases with the same energy density as possible, which are allowed by a given theory. Being applied to the non--supersymmetric two-Higgs doublet extension of the Standard Model (SM) MPP leads to a few different scenarios. In our preferred and best motivated scenario the quartic part of the Higgs effective potential
and Yukawa interactions between Higgs doublets and fermions are invariant under Peccei-Quinn symmetry that ensures the CP conservation in
the Higgs sector and the absence of flavour changing neutral currents in the considered model. In this case the existence of a large
set of degenerate vacua at some high energy scale (\Lambda) also results in a few relations
between Higgs self-coupling constants which can be examined at future colliders. The numerical analysis reveals that these MPP conditions constrain the mass of the SM--like Higgs boson
to lie below 180 GeV for a wide set of the MPP scales \Lambda and \tan\beta . |
Physics Beyond the Standard Model |
"based on: C.D.Froggatt, L.Laperashvili, R.Nevzorov, H.B.Nielsen and M.Sher, Implementation of the multiple point principle in the two-Higgs doublet model of type II, Phys. Rev. D 73 (2006) 095005; arXiv:hep-ph/0602054. " |
r.nevzorov@physics.gla.ac.uk |
| 369 |
Charm and Beauty Production at HERA using dijet events with two leptons in the final state. |
H1 Collaboration |
A measurement is presented of charm and beauty photoproduction
in $ep$ collisions at a centre-of-mass energy of $318 \mbox{ GeV}$.
Data taken by the H1 detector at HERA in the years 1999, 2000, 2004, 2005 and 2006
are analysed. The collected data correspond to an integrated luminosity of $352 \mbox{ pb}^{-1}$.
Events are selected with contain two jets and two leptons in the final state.
The first lepton is a muon, the second either a muon or an electron.
The relative transverse momentum ptrel of the leptons with respect to the associated jet
and the charge and angle correlation of the leptons are exploited to extract the
fractions of charm and beauty event on a statistical basis.
The results are compared with next to leading order QCD calculations
and with leading order QCD calculations supplemented with parton showers. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 370 |
H1 Collaboration |
Measurement of Isolated Photon Production in Deep Inelastic Scattering at
HERA |
Results are presented on the production of isolated photons
ep -> e+\gamma + X in deep-inelastic scattering with a four-momentum transfer squared of
42500 GeV^2.
The cross sections, both inclusive and for events with zero or at least
one additional jet, are measured with the H1 detector at the
electron-proton collider HERA.
The analysis is based on a total integrated luminosity of $227$~pb$^-1$.
The production cross section of isolated
photons with a transverse energy in the range $3 < E_T^\gamma < 10$~GeV
and pseudorapidity range $-1.2 < \eta^\gamma < 1.8$
is measured as a function of $E_T^\gamma$, $\eta^\gamma$ and $Q^2$.
The measured cross section receives contributions from
photon radiation by a quark as well as wide angle, large
$E_T$ bremsstrahlung of the beam lepton..
The data are compared with the predictions from several calculations,
which all underestimate the observed signal, particularly in the low $Q^2$ domain. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 371 |
H1 Collaboration |
Charged Particle Production in High Q2 Deep Inelastic Scattering at HERA |
The average charged track multiplicity and the distribution of the
normalised scaled momentum, $\xp$, of charged final state hadrons are
measured in deep-inelastic $\ep$ scattering at high $Q^2$ in the
Breit frame of reference. This analysis covers the range of photon
virtuality $100 < Q^2 < 20\,000~\GeV^{2}$. Compared with previous
results presented by HERA experiments this analysis has significantly
higher statistics, extends to higher $Q^2$, and to the full range of
$\xp$. The results are compared with $\ee$ annihilation data and with
different models of the fragmentation process. The results are also
compared with an NLO calculation. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 372 |
H1 Collaboration |
Jet Production in Deep-Inelastic Scattering at Low Q^2 at HERA. |
Jet production is studied in deep-inelastic positron-proton scattering at
four momentum transfer squared 5
| Strong Interactions |
|
obehnke@mail.desy.de |
|
| 373 |
H1 Collaboration |
Charm and Beauty Production at HERA using dijet events with two
leptons in the final state |
A measurement is presented of charm and beauty photoproduction
in $ep$ collisions at a centre-of-mass energy of $318 \mbox{ GeV}$.
Data taken by the H1 detector at HERA in the years 1999, 2000, 2004, 2005
and 2006
are analysed. The collected data correspond to an integrated luminosity of
$352 \mbox{ pb}^{-1}$.
Events are selected with contain two jets and two leptons in the final
state.
The first lepton is a muon, the second either a muon or an electron.
The relative transverse momentum ptrel of the leptons with respect to the
associated jet
and the charge and angle correlation of the leptons are exploited to extract
the
fractions of charm and beauty event on a statistical basis.
The results are compared with next to leading order QCD calculations
and with leading order QCD calculations supplemented with parton showers. |
Strong Interactions |
|
obehnke@mail.desy.de |
| 374 |
Jianrong Deng, Al Goshaw, Beate Heinemann, Jefferson Kist, Chris Lester, Ai Nagano, Tom Phillips (for the CDF Collaboration) |
Wgamma and Zgamma Production at the Tevatron |
We present new measurements of the associated production of an
intermediate
vector boson ($W$, $Z$) with a photon using data collected by the CDF
experiment
at the Fermilab Tevatron acelerator at $\sqrt{s}=1.96$~TeV. The data
correspond to
an integrated luminosity of more than 1~fb$^{-1}$. The analysis is
performed by selecting $W$ and
$Z$ boson in their lepton decay modes and by requiring a photon with
transverse energy above $7$~GeV. The cross sections and kinematic
distributions are compared to the Standard Model prediction and
constraints on anomalous couplings among the electroweak gauge bosons
and extracted.
|
High-Energy Electroweak Physics |
|
beate@fnal.gov |
| 375 |
David J Miller |
CP asymmetries in Exotic Higgs decays to Z bosons at the LHC |
The discovery of a Higgs candidate at the LHC will be insufficient to claim Higgs discovery. The quantum numbers and interactions of the Higgs boson must be explored before we can be sure of its role in electroweak symmetry breaking. While it is relatively straightforward to determine whether or not it is a CP even or CP odd state, it is harder to distinguish a CP violating mixture of the two. To this end, we examine the Higgs decay to Z-bosons (followed by the Z decays to leptons) by considering the most general scalar-ZZ vertex, and construct CP violating asymmetries. We find analytic expressions for these asymmetries and explore whether or not they will be visible at the LHC. |
Physics Beyond the Standard Model |
|
d.miller@physics.gla.ac.uk |
| 376 |
Abolfazl Mirjalili |
Higher order predicted terms for some QCD obsevables, using various scale optimazations procedures |
Due to strong dependence of the QCD couplings on the renormalization scheme, there have been a number attempts to resolve the ambiguities inherent in fixed order perturbative calculations. It is interestiong to compare the exact value of NNNLO for some QCD obervables like Higgs decay width to gluon-gluon with the estimates one may derive from the knowledge of NNLO correction through the applications of well known optimization methods. We use the methods based on Fastest
Apparent Converge (FAC), the Principle of Minimal Sensitivity (PMS), the proposed of Brodsky, Lepage and MackenKenzie (BLM) and finally the approach of COmplete Renormalization Group Improvement (CORGI). We extend the technique of FAC, PMS and BLM to predict NNNLO terms for the desired perturbative QCD observables. The results involves
ambiguities on scale setting and the predicted term at required order is not unique while using CORGI approach there are not such difficulties. |
Strong Interactions |
The presented work was resulted from my research activity during my short visiting for three months to DESY in Hamburg (Germany). |
Mirjalili@mail2.ipm.ir |
| 377 |
J.Ruz on behalf of the CAST collaboration |
The CAST Experiment. |
CAST (CERN Axion Solar Telescope) is a helioscope looking for axions coming from the solar core to Earth.
The experiment, located at CERN, is based on the Primakoff effect and use the strength of a magnetic field of 9 Tesla provided by a decommissioned LHC magnet.
CAST is able to face the Sun during sunrise and sunset and therefore three X-ray detectors are placed on both ends of the magnet waiting for a photon from axion-to-photon conversion due to Primakoff effect.
During its first phase that concluded in 2004, CAST looked for axions with masses up to 0.02 eV. The second phase has already started and first data were taken in 2005 and 2006. __So far, CAST´s second phase has managed to reestablish the coherence needed to scan for axions with masses up to 0.38 eV by using a 4He buffer gas that allows the experiment to look into the theoretical regions for the axion.
An extension of CAST phase II is under construction and will allow CAST to extend its sensitivity up to axion masses of 1.16 eV during the following years. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
Jaime.Ruz@cern.ch |
| 378 |
David Eriksson, Stefan Hesselbach, Johan Rathsman |
Associated charged Higgs and W boson production in the MSSM at the CERN Large Hadron Collider |
We investigate the viability of observing charged Higgs bosons (H^+) produced in association with W bosons at the CERN Large Hadron Collider, using the leptonic decay H^+ -> tau^+ nu_tau and hadronic W-decay, within different scenarios of the Minimal Supersymmetric Standard Model (MSSM) with both real and complex parameters. Performing a parton level study we show how the irreducible Standard Model background from W + 2 jets can be controlled by applying appropriate cuts and find that the size of a possible signal depends on the cuts needed to suppress QCD backgrounds and misidentifications. In the standard maximal mixing scenario of the MSSM we find a viable signal for large tan beta and intermediate H^+ masses (~ m_t) when using optimistic cuts whereas for more pessimistic ones we only find a viable signal for very large tan beta (> 50). We have also investigated a special class of MSSM scenarios with large mass-splittings among the heavy Higgs bosons where the cross-section can be resonantly enhanced by factors up to one hundred, with a strong dependence on the CP-violating phases. Even so we find that the signal after cuts remains small except for small masses (<= m_t) with optimistic cuts. Finally, in all the scenarios we have investigated we have only found small CP-asymmetries.
|
Physics Beyond the Standard Model |
|
s.hesselbach@phys.soton.ac.uk |
| 379 |
Ali Murat Guler (for the CHORUS collaboration) |
Measurement of associated charm production in neutrino interactions |
Associated charm production in neutrino-nucleon scattering is a very rare process and therefore difficult to measure. The improvement of automatic scanning systems in the \mbox{CHORUS} experiment allows an efficient search for short-living particles in emulsion to be performed. Hence a search for rare processes such as the associated charm production becomes possible through the observation of the double charm decay topology with a very low background.
In this paper we present a search for
associated charm production in both neutral-current (NC) and
charged-current (CC) $\nu_\mu$ interactions.
About 130,000 $\nu_\mu$ interactions located in the emulsion target have been analysed. Three double charm decays have been observed in the neutral-current (NC) sample with an estimated background of 0.18 $\pm$ 0.05. The relative rate of the associated charm cross-section in DIS
NC $\nu_\mu$ interactions, $\sigma(c\bar{c}
\nu_{\mu})$/$\sigma_\mathrm{NC}^\mathrm{DIS} = (3.76^{+3.07}_{-2.52} \pm 0.56) \times
10^{-3}$ has been measured. One double charm decay has been observed in CC $\nu_\mu$ interactions with an estimated background of 0.18 $\pm$ 0.06. The upper limit on associated charm production at 90\% C.L. in
CC $\nu_\mu$ interactions has been found to be $\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}$.
|
Flavour Physics and CP Violation |
the paper is being submitted for publication |
ali.murat.guler@cern.ch |
| 380 |
Ali Murat Guler (for the CHORUS collaboration) |
Measurement of associated charm production in neutrino interactions |
Associated charm production in neutrino-nucleon scattering is a very rare process and therefore difficult to measure. The improvement of automatic scanning systems in the \mbox{CHORUS} experiment allows an efficient search for short-living particles in emulsion to be performed. Hence a search for rare processes such as the associated charm production becomes possible through the observation of the double charm decay topology with a very low background.
In this paper we present a search for
associated charm production in both neutral-current (NC) and
charged-current (CC) $\nu_\mu$ interactions.
About 130,000 $\nu_\mu$ interactions located in the emulsion target have been analysed. Three double charm decays have been observed in the neutral-current (NC) sample with an estimated background of 0.18 $\pm$ 0.05. The relative rate of the associated charm cross-section in DIS
NC $\nu_\mu$ interactions, $\sigma(c\bar{c}
\nu_{\mu})$/$\sigma_\mathrm{NC}^\mathrm{DIS} = (3.76^{+3.07}_{-2.52} \pm 0.56) \times
10^{-3}$ has been measured. One double charm decay has been observed in CC $\nu_\mu$ interactions with an estimated background of 0.18 $\pm$ 0.06. The upper limit on associated charm production at 90\% C.L. in
CC $\nu_\mu$ interactions has been found to be $\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}$.
|
Neutrino Physics |
the paper is being submitted for publication |
ali.murat.guler@cern.ch |
| 381 |
S. Moretti, S. Munir, P. Poulose |
Explicit CP Violation in the MSSM Through Higgs --> gamma.gamma |
The MSSM with explicit CP violation is studied through the di-photon decay channel of the lightest neutral Higgs boson. Through the leading one-loop order H1 --> gammar.gamma is affected by a large number of Higgs-sparticle couplings, which could be complex. Our preliminary scan over the Supersymmetric parameter space shows that more than 50% average deviations are possible, in either direction, in the corresponding branching ratio, with respect to the case of the CP-conserving MSSM. In particular, our analysis shows that in the presence of a light stop (with mass ~ 200 GeV) a CP-violating phase Arg(mu) ~ 90(deg) can render the H1 --> gamma.gamma branching ratio more than 10 times larger, for suitable combinations of the other MSSM parameters. |
Physics Beyond the Standard Model |
|
poulose@phys.soton.ac.uk |
| 382 |
D0 Collaboration |
B_s Mixing using Semileptonic Decays at Dzero |
We report results on the determination of the B_s oscillation frequency using a large data set taken at the Dzero experiment during RunII of the Tevatron. The Dzero detector was upgraded recently to include an additional layer of silicon close to the beam pipe to significantly improve the decay length resolution. We search for time-dependent oscillations of flavor specific, semileptonic B_s decays where the flavor of the B_s at production is determined by studying inclusive properties of the event. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 383 |
D0 Collaboration |
B_s Mixing using Hadronic Decays at Dzero |
Latest results on the mixing of B_s mesons
from the Dzero experiment at the Fermilab Tevatron Collider will be presented using a
large data set of proton-antiproton collisions. For a precise measurement of the mixing frequency, fully reconstructed decay channels
are desirable since these minimize the ambiguities associated with the boost of the B_s
meson. These decay modes are accessible at
Dzero through the muons originating from semileptonic decays of the other b hadron produced in the event. Using the single muon
data set, we search for time-dependent oscillations of flavor specific, hadronic B_s decays where the flavor of the B_s at
production is determined by the muon as well
as other inclusive properties of the event. Details of the strengths and weaknesses of
this trigger strategy will also be discussed. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 384 |
D0 Collaboration |
Measurements of the CP-Conserving and CP-Violating B_s Mixing Parameters using B_s -> J/psi phi Decays at Dzero |
Using a large data set collected with the
Dzero detector of the Fermilab Tevatron,
we present a study of the decay B_s -> J/psi phi.
From a simultaneous fit to the distributions
in the candidate mass, proper decay length,
and three angles of the decay products, we
obtain the average lifetime of the Bs system,
the width difference between the light and
heavy mass eigenstates, and the CP violating
phase of B_s mixing using all reconstructed
B_s candidates. The flavor of the Bs meson
at production is used in events where this information is available allowing for a
more precise determination of the CP-violating
phase as well as a determination of the
mass difference between the light and heavy
mass eigenstates. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 385 |
D0 Collaboration |
Study of the Charge Asymmetry in Semileptonic Decays of B_s Mesons at Dzero |
We present studies of the charge asymmetry
in semileptonic neutral B meson decays using
a large sample of data collected by the
Dzero detector operating at the Fermilab Tevatron. We present an analysis of the
inclusive asymmetry between positive and
negative like-sign dimuon events containing
contributions from both B_d and B_s mesons.
Knowledge of the asymmetry in Bd mesons
from independent experiments is used to
extract the component of the asymmetry
attributed to B_s mesons. A direct measurement
of the charge asymmetry in B_s mesons is
also presented by comparing the semileptonic
widths of Bs and anti-Bs reconstructed using
the Ds-/+ mu+/- decay channels. Results from
the two analyses are combined to provide
information on the CP violating phase of
B_s mixing. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 386 |
D0 Collaboration |
B_s Lifetime and Width Difference Measurements using B_s Decays to D_s mu X and Ds(*)Ds(*) at Dzero |
We present studies of B_s mesons using a
large sample of D_s mesons associated with a
muon recorded by the Dzero detector operating
at the Fermilab Tevatron. Using the
semileptonic decays B_s -> D_s mu X, we
perform the most precise determination of
the flavor specific B_s lifetime. This
measurement is used to relate the width
difference between the heavy and light mass
eigenstates with the average width of the
eigenstates. A sub sample of the D_s mu data
set containing an extra phi meson is used to
reconstruct Bs decays to two D_s mesons using
the semileptonic decay D_s -> phi mu X.
From this sample, we extract the inclusive
branching fraction Bs to D_s(*)D_s(*) which
can be interpreted as a direct measurement
of width difference between the eigenstates. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 387 |
D0 Collaboration |
Study of Direct CP Violation in B Meson Decay to Final States Containing Charmonium at Dzero |
We study Direct CP violation in
b -> c cbar stransitions by searching for a
charge asymmetry in the decay B+/- -> J/psi K+/-.
The results presented are based on a large data
set of p pbar collisions recorded by the Dzero
detector operating at the Fermilab Tevatron.
By accumulating roughly equal data sets with different configurations of the Dzero magnetic
spectrometers, we are able to obtain the most
precise measurement of this asymmetry. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 388 |
D0 Collaboration |
Study of the Polarization of Upsilons produced in proton –antiproton collisions at Dzero |
Using a large sample of dimuon events recorded
by the Dzero detector operating at the Fermilab
Tevatron, we study the polarization of Upsilons
produced in proton-antiproton collisions at
sqrt(s)=1.96 TeV. The polarization is extracted
as a function of the transverse momentum of the
Upsilon candidate. This measurement provides
valuable information on the study of
non-relativistic QCD, particularly the octet component of quarkonium systems. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 389 |
D0 Collaboration |
Measurement of the Lambda_b Lifetime at Dzero |
We provide two independent measurements of the Lambda_b lifetime. The first is based on a high statistics sample of partially reconstructed semileptonic Lambda b -> Lambda_c mu X decays. The second is based on a smaller sample of fully reconstructed Lambda_b -> J/psi Lambda decays that has the advantage of complete knowledge of the Lambda_b boost. Both analyses are based on a large data set of p pbar collisions recorded by the Dzero detector operating at the Fermilab Tevatron. The results agree well with each other and also with previously published measurements, giving further indication that tau(Lambda_b) < tau(B_d). |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 390 |
D0 Collaboration |
Search for Annihilation Decays of B_s Mesons and Radiative Decays of D+ mesons |
We search for the rare decays B_s -> mu+mu- and D+ -> pi+ mu+ mu- using a large data set of p pbar collisions recorded by the Dzero detector operating at the Fermilab Tevatron. These modes are expected to have sizeable enhancements above the Standard Model rate due to new physics. The B_s annihilation rate is expected to have orders of magnitude enhancement in many supersymmetric models while the radiative charm decays probe scenarios where sizeable new physics contributions are visible in the up-sector quarks but not in the down-sector quarks. We present the most stringent limits on both processes. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 391 |
D0 Collaboration |
Properties of Excited and Heavy b Hadrons |
We study the properties of orbitally excited B_d and B_s mesons as well as heavier b mesons and baryons. The studies are based on a large data set of p pbar collisions recorded by the Dzero detector operating at the Fermilab Tevatron. We explore the mass splitting and production fractions in the B_d** and B_s** system, the mass and lifetime of the Bc meson, and search for new b baryons. We also perform the first measurement of the semileptonic Bs branching fraction to orbitally excited D_s mesons. |
Flavour Physics and CP Violation |
|
"rickv@fnal.gov, hobbs@fnal.gov, bcasey@fnal.gov" |
| 392 |
D0 Collaboration |
Searches for Extra Dimensions and for Heavy Resonances in Dilepton, Diphoton, Electron + Photon and Electron + Missing E_T Final States with the D0 Detector |
The high-mass spectrum of lepton and photon pairs is sensitive to a broad array of new physics. Examples are searches for extra dimensions in different models in the dielectron, dimuon, and diphoton channels, and Z´ bosons with Standard-Model-like couplings to fermions as well as in a variety of GUT-inspired models. A direct search for electron compositeness is possible in the production of excited electrons decaying into electron and photon. In addition, the electron (or muon) plus missing E_T data sample can be searched for a W´ boson. We report on the latest results in searches in the high mass dielectron, dimuon, diphoton, electron plus photon, and electron plus missing E_T channels obtained by the D0 experiment at the Tevatron, using a data set corresponding to an integrated luminosity of about 1 fb^-1, and in most cases substantially exceeding the reach of previous searches. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 393 |
D0 Collaboration |
Search for Supersymmetry with Gauge-Mediated Breaking |
We report the results of a search for supersymmetry (SUSY) with gauge-mediated breaking in the missing transverse energy distribution of inclusive diphoton events using approximately 1.2 fb-1 of data colleced by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. This analysis is the most sensitive probe for the gauge-mediated SUSY models up to date with a short-lived neutralino as the next-lightest SUSY particle. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 394 |
D0 Collaboration |
Search for Large Extra Spatial Dimensions in Jets + Missing E_T Topologies |
A search for signals of large extra spatial dimensions is performed using ~1 fb-1 of data from p-pbar collisions at a center-of-mass energy of 1.96 TeV, collected by the DO detector at the Fermilab Tevatron. The topologies analyzed consist of single jets and acoplanar jets with missing E_T from direct production of gravitons. Constraints on the fundamental Planck scale have been derived. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 395 |
D0 Collaboration |
Search for RPV SUSY in e+mu Final State |
error-replaced by next entry |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 396 |
D0 Collaboration |
Search for RPV SUSY in the e+mu Final State |
We study the production of high p_T electron+muon final states with 1 fb-1 of Dzero RunIIa data. The number of events passing our selection criteria is consistent with the Standard Model(SM) expectation. The distributions of kinematics variables of the final states are also in good agreement with the SM prediction. We set limits on the parameters of a particular Supersymmetric (SUSY) model that predicts an enhancement of the high p_T electron+muon final states via R-Parity Violating production and decay of scaler sneutrino resonances. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 397 |
D0 Collaboration |
Searches for Leptoquark Production in pp(bar) Collisions at the D0 Experiment |
We report on searches for the production of scalar and vector leptoquarks in pp(bar) collisions at the Tevatron collider, which are based on integrated luminosities of up to 1 fb-1 collected with the D0 detector. Leptoquarks, which are predicted by several extensions of the Standard Model, are hypothetical particles carrying both lepton and quark flavors. At hadron colliders they can either be pair-produced via the strong interaction or a single leptoquark can be produced in association with a lepton via the hypothesized leptoquark-lepton-quark coupling
Searches for the pair-production of leptoquarks of all three generations have been performed using the LQ-LQ(bar) ->l^+l^-qq(bar), l^\pm nu qq(bar), and nunu(bar)qq(bar) final states. A search for the single production of leptoquarks coupling to muons is based on the decay channel LQ mu -> mu q mu$. Upper limits on the production cross sections are given and are used to derive lower limits on the leptoquark masses. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 398 |
D0 Collaboration |
Searches for Squarks and Gluinos in Jets+Missing Transverse Energy Final States |
Searches in the framework of R-parity conserving supergravity inspired models have been performed in data collected by the D0 detector at the Tevatron pp(bar) collider at a center-of-mass energy of sqrt{s} = 1.96 TeV. Topologies analyzed consist of acoplanar-jets and multijets events with large missing transvers energy in the final state. In the first search, generic squarks and gluinos productions were investigated in 1 fb-1 of data. The data show good agreement with the standard model expectations and improved mass limits have been derived. Lower limits of 375 GeV and 289 GeV are derived at 95% CL on the squarks and gluino masses, respectively, with tan(beta) = 3, A_0 = 0 and \mu < 0. Previous limits obtained by D0 collaboration are improved by about 50 GeV.
Supergravity inspired models suggest the existence of light supersymmetric partners of the third generation quarks: a light stop for moderate values of tan(beta), a light sbottom for large tan(beta). If the stop or sbottom is the next-to-lightest supersymmetric particle, the expected decay channels are \tilde{t} -> c chi^0_1 and \tilde{b} -> b chi^0_1, respectively, with \chi^0_1 assumed to be the lightest supersymmetric particle. Pair production of stops or sbottoms will therefore lead to the signature of two acoplanar heavy flavor jets and missing transverse energy. The searches for such final states are performed, improving significantly upon the results from Run I of the Tevatron. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 399 |
D0 Collaboration |
Search for the Associated Production of Charginos and Neutralinos with the D0 Detector |
A search for associated production of charginos and neutralinos is performed using data recorded with the D0 detector at a p-pbar center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider. This analysis considers final states with missing transverse energy and three leptons, including hadronic decays of tau leptons. With more than 2 fb-1 of data recorded by the D0 experiment, the expected sensitivity reaches well beyond existing limits on the chargino mass, in particular in regions of parameter space with enhanced leptonic branching fractions. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,grivaz@lal.in2p3.fr" |
| 400 |
D0 Collaboration |
Measurement of the tt(bar) Production Cross Section at D0 in the Lepton+Jets Channel |
We present measuremets of the tt(bar) production cross section at a center-of-mass energy of 1.96 TeV. The analyses is based on the selection of events with one charged lepton (electron or muon), missing transverse energy, and 3 or more jets with p_T > 20 GeV and |η| < 2.5. We utilize up to 1 fb-1 of data samples collected using the D0 detector. We separate the tt(bar) signal from background processes using kinematic information. A subset of measurements use algorithms to identify b-quark jets that are associated with top quark decays. Neural Network algorithm that use lifetime information and soft lepton tagging are employed. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 401 |
D0 Collaboration |
Measurement of the tt(bar) cross section at D0 in the dilepton channel |
We report on the measurement of the production cross section of tt(bar) quark pairs decaying in the dilepton mode. This analysis is based on data taken with the D0 Detector at the Fermilab Tevatron pp(bar)-collider at a center-of-mass energy of 1.96 TeV. The data corresponding to an integrated luminosity of about 1.1 fb−1 were recorded in the years 2002 to 2006. We consider final states with two well-identified leptons in the final state as well as one lepton and one track. In the latter case, we use information from b-jet identification algorithm to suppress background. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 402 |
D0 Collaboration |
Measurement of the tt(bar) Production Cross Section at D0 using All-Hadronic and tau+Jet Events |
We report on the measurement of the tt(bar) production cross section with candidate events in the all-hadronic and tau+jets final state. For the tau+jet channel we select events in which the tau lepton subsequently decays to one or three charged hadrons plus neutral hadrons and a neutrino. We separate the tt(bar) signal from the QCD multijet background by requiring at least one b-tagged jet and by using kinematic criteria. Different approaches to furhter improve the accuracy of the cross section measurement in the all-hadronic sample are presented. Several kinematic criteria are combined into a neural network in one method, while invariant masses of jet combinations to reconstruct the W boson and top quark mass are used in another measurement. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 403 |
D0 Collaboration |
Measurement of the Top Quark Mass at D0 in the Lepton+Jets Channel |
We report on measurements of the top quark mass using tt(bar) candidates in the lepton+jets final state. Up to 1 fb-1 of data collected with the D0 experiment are utilized. For each event, a probability is calculated as a function of the top mass and the overall jet energy scale. The probability is based on the differential cross section for t-tbar production or a kinematic event reconstruction. The top mass and jet energy scale are extracted by maximizing a likelihood constructed as the product of the single event probabilities. The overall jet energy scale is constraint by the two jets from the hadronic W boson decay. Further sensitivity is obtained by methods utilizing information coming from b jet identification |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 404 |
D0 Collaboration |
Measurement of the Top Quark Mass at D0 using All-Hadronic Events |
We report on the measurement of the top quark mass using tt(bar) candidates in the all-hadronic decay channel. The tt(bar) signal was discriminated from background using kinematic information and by requiring two identified b jets. The mass was extracted by comparing templates of tt(bar) signal and multi-jet background to the selected candidates. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 405 |
D0 Collaboration |
Measurement of the Top Quark Mass at D0 using Dilepton Events |
We present measurements of the top quark mass in the dilepton channel based on approximately 1 fb−1 of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. The kinematics of these events are not sufficiently constrained by the observed final state to reconstruct the top quark mass. With different methods, we compute a likelihood for the observed events to occur for a range of assumed top quark masses. For each event we extract estimators for the top quark mass from this likelihood. We compare the distribution of the estimators for all events to Monte Carlo predictions for different input top quark masses in a maximum likelihood fit to extract the top quark mass. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 406 |
D0 Collaboration |
Probing the SM with Top Quark Events |
We report on several measurements probing the standard model in top quark events. We present a measurement of the ratio R = B(t -> W b)/B(t -> W q), which is expected to exceed 0.998 at the 95% confidence level. Experimentally, we measure the ratio based on the fraction of candidate events with 0, 1, or 2 b-tagged jets. We also report on a measurement of the charge of the top quark by resolving the kinematic ambiguity between the standard model scenario of a charge 2/3 top quark and an exotic scenario of a charge −4/3 quark. Top quark events provide a unique sample to measure the helicity of the W boson. We report on a measurement of the fraction of right-handed W bosons in top quark decay, which is consistent with the null expectation from the standard model. We also report on the measurement of forward-backward asymmetry in tt(bar) production in proton-antiproton collisions. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 407 |
D0 Collaboration |
Single op Quark Production at D0 and Direct Measurement of |V_tb| |
We report on several measurements probing the standard model in top quark events. We present a measurement of the ratio R = B(t -> W b)/B(t -> W q), which is expected to exceed 0.998 at the 95% confidence level. Experimentally, we measure the ratio based on the fraction of candidate events with 0, 1, or 2 b-tagged jets. We also report on a measurement of the charge of the top quark by resolving the kinematic ambiguity between the standard model scenario of a charge 2/3 top quark and an exotic scenario of a charge −4/3 quark. Top quark events provide a unique sample to measure the helicity of the W boson. We report on a measurement of the fraction of right-handed W bosons in top quark decay, which is consistent with the null expectation from the standard model. We also report on the measurement of forward-backward asymmetry in tt(bar) production in proton-antiproton collisions. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 408 |
D0 Collaboration |
Single Top Quark Production at D0 and Direct Measurement of |V_tb| |
We report on the evidence for single top quark production in proton-antiproton collisions using a dataset of almost 1 fb−1 collected with the D0 detector. Single top quarks are expected to be produced in association with bottom quarks through the exchange of a W boson in the s-channel and the t-channel. We select events with one energetic electron or muon, missing transverse energy, and two, three or four jets, with at least one b-tagged jet. Several complementary measurements using neural net discriminants, decision trees and a matrix element technique are presented. All measurements are consistent among each other and measure a cross section compatible with the Standard Model prediction for electroweak production of single top. The combination of the different analyses shows evidence for single top quark production We also present the first direct measurement of the CKM matrix element |V_tb|. |
High-Energy Electroweak Physics |
*** Note ***: the previous abstract of the same title was went with incorrect abstract text. This is the correct one. |
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 409 |
D0 Collaboration |
Search for Associated Production of W and Higgs Bosons in l-nu-bb Final States |
We present preliminary results of a search for the Higgs boson through its associated production with W for masses between 105 and 155 GeV in ppbar collisions at sqrt(s) = 1.96 TeV. The search is performed in events containing one lepton (electron or muon), an imbalance in the transverse energy, and two b-tagged jets. We compare results obtained in two approaches, one of them relying on a sequence of kinematic cuts, and another one separating signal from background using leading-order matrix element description of relevant physics processes. The search is based on 1.0 fb^-1 of integrated luminosity accumulated by the D0 experiment at Fermilab. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 410 |
D0 Collaboration |
Search for Associated Production of Z and Higgs Bosons in l+l- bb Final States |
Studies are presented of the search for a light (105-155 GeV) Standard Model Higgs boson produced in association with a Z boson in the Z->l+l- (l= electron or muon) and H->bb decay channel using 0.9 fb^-1 of integrated luminosity of Run II data collected by the D0 detector at the Fermilab pp(bar) collider at sqrt(s) = 1.96 TeV. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 411 |
D0 Collaboration |
Search for Associated Production of Z and Higgs Bosons in nunu bb Final States |
Studies are presented from the D0 experiment at Fermilab for the search for a light Standard Model Higgs Boson in association with a Z boson, which decays invisibly to a pair of neutrinos using 0.9 fb^-1 of integrated luminosity of Run II data. This channel relies on the identification of two b-tagged jets from the Higgs Boson decay and on the measurement of a large imbalance in the transverse energy of the event. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 412 |
D0 Collaboration |
Search for Higgs Bosons in WW(*)->l+l'- Decays |
The process H->WW(*)->l+l'- (l,l' = e,mu) is studied in ppbar collisions at the center of mass energy sqrt(s) = 1.96 TeV with the upgraded D0 detector at the Fermilab Tevatron accelerator. A Higgs particle with a mass greater than 140 GeV primarily decays into a of W-bosons and the semi-leptonic decay channels of the W provide a clear signature. Besides the search for the Standard Model Higgs, exotic models with enhanced Higgs production cross sections are already probed with data corresponding to integrated luminosity of 0.9 pb^-1. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 413 |
D0 Collaboration |
Search for Higgs Bosons in WW(*)->ltau Decays |
We present a search for a Standard Model Higgs Boson in the process H->WW(*)->tau+tau- where one of the taus decays into a muon and neutrino and the other one decays hadronically. Analysis of this channel would improve the current limits of Higgs production cross section due to a large tau->hadrons branching fraction. The results are obtained using 0.9 fb^-1 of data collected by the D0 detector at the Tevatron. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 414 |
D0 Collaboration |
Combined Upper Limit on Standard Model Higgs Boson Production at D0 |
A combination of several searches for Standard Model Higgs boson production at D0 is presented. The contributing processes include associated production (WH->lnu bb, ZH->nunu bb, ZH->ll bb) and gluonfusion (gg->H->WW). Analyses are performed on Run II data corresponding to 1 pb^-1 of integrated luminosity. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,gregorio@in2p3.fr" |
| 415 |
D0 Collaboration |
Search for New Physics in Top Quark Events |
The large mass of the top quark, close to the electroweak symmetry-breaking scale, makes it a good candidate for probing physics beyond the Standard Model. Single top quarks may be produced in the decay of a new heavy gauge boson W' and we present limits on the production cross section and the mass of such a W' assuming standard model like couplings. We also search for single top production through flavor changing neutral currents involving gluon, Z boson, or photon exchange. We also search for non-standard model signatures in top pair events. Models for new physics beyond the standard model are probed by looking at possible different event kinematics or deviations in the measured total or differential cross section. |
Physics Beyond the Standard Model |
|
"rickv@fnal.gov,hobbs@fnal.gov,webermi@fnal.gov" |
| 416 |
Vladimir Lasukov |
Radioactive decay of Lemaître’s atom |
The paper studies a quantum theory of the early Universe with a negative cosmological constant. A gravitational analog of the non stationary perturbation theory is developed within which the production of the scalar-field massive quanta by gravitational atoms is studied. |
Astroparticle Physics, Gravitational Waves and Cosmology |
|
lav_8@list.ru |
| 417 |
Maurice LALOUM |
STRUCTURE OF THE GALAXY, MATTER-ANTIMATTER ANNIHILATION, AND ORIGIN OF THE COSMIC RAYS |
We present a theory of the origin of the observed cosmic rays, especially at the highest energies known, involving matter-antimatter annihilation in the median plane of the Milky Way. Accordingly, we discuss the structure and equilibrium of the Galaxy, seen as made of two parallel disks of matter versus antimatter dominance, opposed through the repulsion of an annihilation gas, settled in the equator disk. The admitted suppression of antimatter in the Universe, after the "big-bang", is questioned. Various tests performed, indeed, tend to confirm our theory; in particilar, the now classical power-law energy behaviour of the incident flux of energetic cosmic rays is easily derived, with quite expected exponents of -2.5 and -3 (main dependence, including the first knee). Ultra-high energies, further, are easily attainable, with no necessary restriction of the GZK kind, for instance. Beyond 10^20 eV, rather, a new break is still made possible with steeper logarithmic slope, as hinted by data. The overall equilibrium of the Galaxy is examined; in particular, the mechanical stability of globular clusters, which is deeply paradoxical in usual stances, now appears quite explainable in this theory. |
Astroparticle Physics, Gravitational Waves and Cosmology |
"A second paper about neutrinos (axiomatic view on formalism, and consecutive physical predictions),in preparation, might still be presented : ""Quantum Mechanics and Neutrino Oscillation""" |
Maurice.Laloum@lpnhe.in2p3.fr |
| 418 |
Maurice LALOUM |
STRUCTURE OF THE GALAXY, MATTER-ANTIMATTER ANNIHILATION, AND ORIGIN OF THE COSMIC RAYS |
We present a theory of the origin of the observed cosmic rays, especially at the highest energies known, involving matter-antimatter annihilation in the median plane of the Milky Way. Accordingly, we discuss the structure and equilibrium of the Galaxy, seen as made of two parallel disks of matter versus antimatter dominance, opposed through the repulsion of an annihilation gas, settled in the equator disk. The admitted suppression of antimatter in the Universe, after the "big-bang", is questioned. Various tests performed, indeed, tend to confirm our theory; in particilar, the now classical power-law energy behaviour of the incident flux of energetic cosmic rays is easily derived, with quite expected exponents of -2.5 and -3 (main dependence, including the first knee). Ultra-high energies, further, are easily attainable, with no necessary restriction of the GZK kind, for instance. Beyond 10^20 eV, rather, a new break is still made possible with steeper logarithmic slope, as hinted by data. The overall equilibrium of the Galaxy is examined; in particular, the mechanical stability of globular clusters, which is deeply paradoxical in usual stances, now appears quite explainable in this theory. |
Astroparticle Physics, Gravitational Waves and Cosmology |
"A second paper about neutrinos (axiomatic view on formalism, and consecutive physical predictions),in preparation, might still be presented : ""Quantum Mechanics and Neutrino Oscillation""" |
Maurice.Laloum@lpnhe.in2p3.fr |
| 419 |
Maurice LALOUM |
Quantum Mechanics and Neutrino Oscillation |
We argue that the present classical formalism of neutrino oscillation is only approximate and should require several second-order corrections : kinetic internal dispersion, violation of the very principles of Quantum Mechanics, non-hermiticity of the Hamiltonian operator, finite actual lifetimes, neutrino mass matrix duly of the CKM classical type, existence of probability waves, making credibility to intense radiation from about "Black Holes" (faking "White Wells"). |
Neutrino Physics |
|
Maurice.Laloum@lpnhe.in2p3.fr |
| 420 |
Franco Bradamante on behalf of the COMPASS Collaboration |
Transverse Spin Effects at COMPASS |
To fully specify the quark structure of the nucleon at the twist-two level, three quark distribution functions have to be taken into account: the unpolarised distributions, the helicity distributions and the transverse spin distributions (or transversity). The measurement of transversity in semi-inclusive deep-inelastic scattering via the Collins effect was the main motivation for the measurements of transverse spin effects proposed by the COMPASS experiment at CERN and by the HERMES experiment at DESY. The measurement of transverse spin effects in transversely polarized proton-proton scattering is also an important part of the physics programme of the RHIC-Spin experiments at BNL. In the mean time, the relevance of the Transverse Momentum Dependent (TMD) parton distribution functions, like the Sivers function, became more clear, and is being investigated in the same experiments.
In the years 2002, 2003, and 2004 the COMPASS Collaboration has dedicated about 20% of the allocated beam time to the measurement of transverse spin asymmetries using a transversely polarised LiD target and the μ beam of the CERN SPS, set at 160 GeV/c momentum.
The analysis of single spin asymmetries of both identified and non-identified hadrons has been now finalized. A total of 10.5 millions of DIS events (Q^2 > 1 GeV^2) have been reconstructed and results are given for all the channels investigated in so far. The Collins and the Sivers asymmetries of both the leading hadron and all the hadrons on deuteron, measured by COMPASS for the first time, are small, if any. The small statistical errors (the systematic errors are believed to be considerably smaller) allow to put tight constrains on the relative contribution of the d quark, when analysed together with the recent HERMES proton data and the Belle measurements of the Collins functions. The COMPASS results for the two-hadron asymmetries and for Lambda polarisation, which are two alternative ways to address transversity, are also presented. Very recently, results have been obtained for the other six TMD azimuthal asymmetries related to the azimuthal modulations which possibly appear in the cross-section of SIDIS on a transversely polarized target.
The plans for future measurements are also presented. |
Strong Interactions |
|
franco.bradamante@ts.infn.it |
| 421 |
J.L. Raaf for the Super-Kamiokande Collaboration |
Recent atmospheric neutrino results using the SK-I and SK-II datasets |
We present recent results from analyses of atmospheric neutrino data using the Super-Kamiokande water Cherenkov detector, which has a fiducial volume of 22,500 tons of ultra-pure water. Data from two major running periods of SK are used in the analyses: SK-I (40% photomultiplier coverage) and SK-II (20% photomultiplier coverage). |
Neutrino Physics |
I'm sorry this is late! |
jlraaf@bu.edu |
| 422 |
D0 Collaboration |
A Precision Determination of the Z0 Cross Section at D0 |
We present a measurement of the production cross section for $Z0$ bosons in the D0 experiment at the Fermilab Tevatron. Z^0/gamma* production is detected in the e^+e^- and mu^+mu^- decay modes for dilepton masses between 60 and 130 GeV/c$^2$.
A data sample of $\sim$ 75,000 leptonic decays is observed in 1 fb-1 of integrated luminosity. After correction for acceptance, detection efficiencies and QED effects, the total Z^0 production cross section is extracted. Comparison of this cross section with recent NNLO
calculations provides a calibration of the luminosity constants used at hadron colliders. Alternatively, the ratio of the cross sections of
other high p_T processes to the Z^/gamma^* cross section may yield more precise results than the present technique of normalizing collider cross sections to the total proton anti-proton inelastic scattering cross section. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 423 |
D0 Collaboration |
Precision Study of Z-gamma Production at D0 |
D0 presents a study of \ell\ell\gamma events, where \ell stands for either an electron or a muon, using more than 1 fb-1 of data collected with the D0 detector at the Fermilab Tevatron pp(bar) Collider at sqrt{s} = 1.96 TeV. A total of 453 (437) candidates are observed in the e-e-gamma (mu-mu-gamma) final state, allowing the highest precision measurement to date of the Z-gamma cross section at a hadron collider. The most restrictive limits to date are also set on anomalous trilinear Z-gamma-gamma and Z-Z-gamma gauge boson couplings up to a new physics scale of Lambda = 1.2 TeV. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 424 |
D0 Collaboration |
Measurement of the Z Rapidity Distribution using Di-electron events with 0.4 fb-1 of data at sqrt(s)=1960 GeV |
D0 presents a measurement of the shape of the boson rapidity distribution for pp(bar) -> Z/gamma* -> e^+e^- +X events.The measurement is made using events with mass between 71 < M_{ee} < 111 GeV and uses 0.4 fb-1 of data collected at the Fermilab Tevatron Collider. At Run~II energies, the boson rapidity reaches to rapidity y ~3. The acceptance of the D0 detector extends to rapidities of 2.8. This measurement significantly improves the uncertainties on the rapidity distribution in the forward region compared with previous measurements. A NNLO calculation is compared to our data and found to be in good agreement. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 425 |
D0 Collaboration |
W+W- Pair Production at D0 |
D0 presents a measurement of the WW production cross section at theTevatron, using the fully leptonic decay modes ee, emu, and mumu, and a data set of fb-1. Limits on trilinear gauge couplings are determined using the kinematics of WW events. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 426 |
D0 Collaboration |
A Measurement of the W Charge Asymmetry to Large Rapidity at D0 |
D0 presents a W charge asymmetry measurement in electron channel in rapidity bins up to 3.2 using 1 fb-1 data. Implications for improved determination of parton distribution functions are presented. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 427 |
D0 Collaboration |
Measurement of W-gamma Production at D0 |
The coupling parameters for the W-W-photon vertex are studied by using final state lepton (electron or muon), neutrino, and photon events that were collected at the D0 detector and delivered by the Fermilab Tevatron Collider at a center-of-mass energy of 1.96 TeV. Physical features of the W-W-photon gauge coupling are discussed. The importance of the Standard Model radiation amplitude zero in the photon-lepton charge signed rapidity difference is detailed and the distribution from data is presented. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 428 |
D0 Collaboration |
WZ Production at D0 |
D0 presents the results of a search for WZ diboson production and measurement of the WZ production cross section at the Tevatron in the three lepton (electron or muon) plus missing transverse energy channels using a data set of 1 fb-1.
|
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobbs@fnal.gov,bolton@phys.ksu.edu" |
| 429 |
D0 Collaboration |
A Search for Z Boson Pair Production at the Tevatron |
D0 presents a search for Z boson pair production in final states where both Z bosons decay to lepton or muon pairs. The search uses 1 fb-1 of data at sqrt(s)=1.96 TeV collected with the D0 detector at the Fermilab Tevatron. |
High-Energy Electroweak Physics |
|
"rickv@fnal.gov,hobb@fnal.gov,bolton@phys.ksu.edu" |
| 430 |
Y.Mikami, O.Miller, V.Rajovic, N.K.Watson, J.A.Wilson, J.A.Ballin, P.D.Dauncey, A.-M. Magnan, M.Noy (ImperialJ.P.Crooks, M.Stanitzki, K.D.Stefanov, R.Turchetta, M.Tyndel, E.G.Villani |
A MAPS-based readout of an electromagnetic calorimeter for the ILC |
To extract the physics required at the International Linear Collider, the detectors will need an unprecedented hadronic jet energy resolution. For the electromagnetic calorimeter, the use of a silicon-tungsten sampling calorimeters with a highly granular readout has been proposed. The CALICE collaboration is studying options for the sensitive silicon
detectors together with common solutions for mechanical structures and readout. The status of one silicon sensor option, which uses Monolithic Active Pixel Sensors (MAPS), will be presented. This novel design would have extremely fine granularity with binary pixel readout integrated into the sensor. This effectively leads to a "tera-pixel" electromagnetic calorimeter
system. A overview of the MAPS concept will be given along with the potential advantages of this design. The status of the production of a proof-of-concept sensor will be presented, together with simulation results showing the
expected detector and physics performance. |
Detectors and Data Handling |
|
M.M.Stanitzki@rl.ac.uk |
| 431 |
Olga Mena, Christopher Orme, Sergio Palomares-Ruiz, Silvia Pascoli |
Phenomenology of intermediate gamma beta-beams |
We discuss the benefits of using intermediate gamma beta-beams in helping resolve the outstanding problems in neutrino mixing. We present simulations for the CERN-Canfranc and CERN-Boulby baselines before comparing with other Phase II analyses. Possible synergies with alternative Phase II neutrino oscillation experiments will be highlighted. |
Neutrino Physics |
|
c..d.orme@durham.ac.uk |
| 432 |
Valeria Bartsch, Daniel Beecher, Ilija Bizjak, Mark Lancaster, Sarah Malik, Emily Nurse, Troy Vine, David Waters (for the CDF Collaboration) |
Direct Measurement of the W Boson Width |
We present a direct measurement of the $W$ boson width using 370
$pb^{-1}$ and 330 $pb^{-1}$ of data collected with the CDF II detector
for the electron and muon decay channels respectively. The measurement
is made by fitting to the tail of the transverse mass distribution,
exploiting the slower fall-off of the Breit Wigner width component
compared to the Gaussian resolution component. |
High-Energy Electroweak Physics |
|
nurse@fnal.gov |
| 433 |
Olga Mena, Christopher Orme, Sergio Palomares-Ruiz, Silvia Pascoli |
Phenomenology of intermediate gamma beta-beams |
We discuss the benefits of using intermediate gamma beta-beams in helping resolve the outstanding problems in neutrino mixing. We present simulations for the CERN-Canfranc and CERN-Boulby baselines before comparing with other Phase II analyses. Possible synergies with alternative Phase II neutrino oscillation experiments will be highlighted. |
Neutrino Physics |
The email sent previous had an error. |
c.d.orme@durham.ac.uk |
| 434 |
gf |
bvc |
vcx |
High-Energy Nuclear Physics |
|
tt@rediffmail.com |
| 435 |
LHCb collaboration |
Rare B decays at LHCb |
The LHCb experiment will search for New Physics in Bs -> mumu decays using the data collected during the very first physics run of LHC, with a 90% CL exclusion sensitivity down to the SM prediction. The latest expectations, based on MC studies with fully simulated events, will be presented. The LHCb sensitivity to other rare and radiative B decays will also be reviewed.
|
Flavour Physics and CP Violation |
|
Olivier.Schneider@epfl.ch |
| 436 |
LHCb collaboration |
Time-dependent CP asymmetries in Bs decays at LHCb |
The LHCb experiment will search for New Physics in Bs mixing, notably through the measurement of the Bs mixing phase from the time-dependent CP asymmetry in exclusive Bs decays governed by the b ->ccbar s quark-level transition. Large New Physics effects can be discovered or excluded with the data collected during the very first physics run of LHC. The latest expectat
|