## Particle Physics Seminars 2005

Seminars 2003     Seminars 2004 (First Half)     Seminars 2004 (Second Half)

Normal seminar coordinates :

Wed 2-3pm, Moseley Lecture Theatre

 Wed 09 Feb Prof Terry Wyatt (Manchester) Schuster Colloquium

 Thur 17 Feb, 5:00-6:00 pm 5th Floor HEP Meeting Room Dr. E. Aguilo (Barcelona)

Physics features of the SPD within the LHCb Calorimetry System  (Abstract)

 Thur 24 Feb, 2-3 pm 2nd Floor Seminar Room Dr. A. Nomerotski (FNAL)

B physics at the Tevatron    (Abstract)

 Wed 02 Mar Dr. E. Gardi (Cambridge)

Inclusive B-decay Spectra and Infrared Renormalons    (Abstract)

 Wed 09 Mar Dr. B. C. Allanach (DAMTP)

Requirements on Collider Data to Match the Precision of WMAP on Supersymmetric Dark Matter    (Abstract)

 Wed 16 Mar Prof. Albert Ziljstra (Manchester) Schuster Colloquium

 Wed 13 Apr Dr. C. Touramanis (Liverpool)

Measurements of the CKM angles alpha and gamma in BABAR

 Wed 20 Apr Dr. S. Cartwright (Sheffield)

Neutrino Oscillations - the Next(-But-One?) Generation    (Abstract)

 Wed 27 Apr Prof. Niels Walet (Manchester) Schuster Colloquium

 Wed 04 May Dr. S. A. Abel (Durham, IPPP)

Interactions on D-branes and their uses    (Abstract)

 Wed 11 May Project reports of 1st year students (Ph.D & M.Sc)

## Abstracts

17 Feb.   E. Aguilo :
LHCb is an experiment in construction dedicated to CP violation in the B sector. The SPD (Scintillator Pad Detector) is a scintillator tile plane in front of the LHCb electromagnetic calorimeter to differentiate at first level trigger (L0) between electrons and photons. In this talk three Physics subjects related to the SPD will be introduced: a pulseshape simulation of the detector, a study for the optimisation of the L0 trigger and an analysis to improve the $B_d \to J/\psi (e^+e^-) K_S$ channel reconstructed measurements.

24 Feb.   A. Nomerotski :
Since its discovery in 1977 the bottom quark played a prominent role in the Standard Model of elementary particles due to its heaviness and long lifetime. These unique features allowed to develop special approaches to study its properties both in theory and experimental techniques. The talk will review new results on B-physics from the DZero detector at Fermilab. The emphasis will be done on the lifetime and oscillation measurements which require precision tracking with silicon detectors.

02 Mar.   E. Gardi :
We show that the B \to X(s) gamma photon energy (E_gamma) spectrum can be reliably computed by resummed perturbation theory. Our calculation is based on Dressed Gluon Exponentiation (DGE) incorporating Sudakov and renormalon resummation. It is shown that the resummed spectrum does not have the perturbative support properties: it smoothly extends to the non-perturbative region E_gamma > m/2, where m is the quark pole mass, and tends to zero near the physical endpoint. The calculation of the Sudakov factor, which determines the shape of the spectrum in the peak region, as well as that of the pole mass, which sets the energy scale, are performed using Principal-Value Borel summation. By using the same prescription in both, the cancellation of the leading renormalon ambiguity is respected. Furthermore, in computing the Sudakov exponent we go beyond the formal next-to-next-to-leading logarithmic accuracy using the large-order asymptotic behavior of the series, which is accurately determined from the relation with the pole mass. Upon matching the resummed result with the next-to-leading order expression we compute the spectrum, obtain its moments as a function of a minimum photon energy cut, analyze sources of uncertainty and show that our predictions are in good agreement with Belle data.

09 Mar.   B. Allanach :
If future colliders discover supersymmetric particles and probe their properties, one could predict the dark matter density of the Universe and would constrain cosmology with the help of precision data provided by WMAP and PLANCK. We investigate how well the relic density can be predicted in minimal supergravity (mSUGRA), with and without the assumption of mSUGRA when analysing data. We determine the parameters to which the relic density is most sensitive, and quantify the collider accuracy needed. Theoretical errors in the prediction are investigated in some detail.

20 Apr.   S. Cartwright :
Over the past 40 years, Nobel Prize-winning experiments have demonstrated that electron neutrinos produced in solar fusion can transform into another type before they reach Earth, and that the two heavier mass eigenstates are essentially a 50:50 mix of mu and tau neutrinos. That leaves one mixing angle unaccounted for - does the electron neutrino mix to the heavier of the two other states? This apparently minor question may hold the key to one of the longest-standing problems of particle cosmology: why the universe is made of matter and not antimatter. The T2K experiment in Japan is a next-generation long baseline oscillation experiment, which aims to investigate the third mixing angle and possibly to shed some light on the matter/antimatter asymmetry of the universe. I will talk about neutrinos and their oscillations, the concept and aims of the T2K experiment and its design challenges, and the physics prospects when the project turns on in 2009.

04 May.   S. A. Abel :
D-branes are a useful tool for examining the properties of theories with extra dimensions, with the added convenience of renormalisability and UV finiteness. In this talk I discuss some of the questions that can be addressed in this formalism including power law running and FCNCs.

Email: JSLEE