ParticlePhysicsSeminars2004

Seminars 2003 page
Seminars 2004 (First Half) page

Normal seminar coordinates :
Wed 2-3pm, Moseley Lecture Theatre

 Wed   6 Oct Dr. L. Dixon (SLAC)
NNLO rapidity distributions for lepton pair production at hadron colliders   (Abstract)

 Wed 20 Oct Dr. D. Lavin (Edinburgh)
Analysis of B0 -> K*+pi- at BaBar   (Abstract)

 Wed 27 Oct Mr. T. Underwood (Manchester)
Low scale resonant leptogenesis - a phenomenological perspective   (Abstract)

 Wed   3 Nov Dr. K. Peters (DESY)
Higher Order Corrections to Vector Boson Scattering at Small Scattering Angles   (Abstract)

 Mon   8 Nov, 1:00pm, Bragg Lecture Theatre Dr. R. Saakyan (UCL)
Neutrinoless double beta decay: Present and Future   (Abstract)

 Wed 17 Nov Prof. L. Roszkowski (Sheffield)
Supersymmetric Dark Matter   (Abstract)

 Wed 24 Nov Dr. D. Miller (Glasgow)
The measurement of SUSY masses via cascade decays at the LHC   (Abstract)

 Wed   1 Dec Dr. M. Dasgupta (Manchester)
Soft QCD - the hard facts   (Abstract)

 Wed   8 Dec, 2.30pm, Bragg Lecture Theatre Prof. S. Edwards (Cambridge) SCHUSTER COLLOQUIUM

Abstracts

6 Oct. L. Dixon:
The measurement of W and Z production at the Tevatron and LHC is a benchmark test of QCD as well as electroweak theory. The rapidity distribution provides a stringent constraint on parton distribution functions, and can be used to normalize the "partonic" luminosity at the detector. I describe the computation of this distribution at NNLO in QCD [hep-ph/0312266], which leads to sub-1-percent theoretical uncertainties for vector boson production at the LHC. Phase space integrals are performed using a novel integration-by-parts method. The application to fixed target Drell-Yan data is also discussed.

20 Oct. D. Lavin:
The talk will present an analysis of the rare hadronic B decay B0 -> K*+pi- , K*+ -> K+pi0 with the summer 2002 dataset of 81 fb-1 recorded with the BaBar detector. B0 ->K*+pi- is an interesting decay mode as it is a potential mode in which to observe direct CP violation. The analysis is based on the method of maximum likelihood which is used to determine the signal yield and hence make a measurement of the branching fraction.

27 Oct. T. Underwood:
Why is there more matter than antimatter in the universe? Why do neutrinos have mass? Might these phenomena be connected? The minimal Standard Model does not provide an answer to any of these questions.

Leptogenesis is an interesting model linking massive neutrinos to the baryon asymmetry of the universe. Unfortunately most of the physics involved in `traditional' leptogenesis would take place at extremely high energies (about 10^9 GeV) -- this limits its testability, and causes problems with SUSY models.

Resonant leptogenesis is a scenario where the scale can be lowered to less than 1 TeV completely consistently with neutrino data. It has the nice feature that the final baryon asymmetry does not rely on specific initial conditions, it may also predict observable lepton flavour violation and possibly has heavy Majorana neutrinos that could be produced at colliders. All this in a very minimal extension of the Standard Model.

3 Nov. K. Peters:
We investigate resummed QCD and EW corrections to vector boson scattering at small scattering angles. QCD corrections are present since, like the photon, all vector bosons may dissociate into quark-antiquark pairs. These dipoles interact through gluon exchanges. Particularly numerical results for the process $\gamma\gamma\to ZZ$ will be discussed. In the second part of the talk a resummation programme for the EW sector at small scattering angles will be presented.

8 Nov. R. Saakyan:
One of the most exciting results of the last decade has been the growing evidence that neutrinos are massive established by neutrino oscillation experiments. However, there are two fundamental questions that can not be answered by oscillations experiments. One of them is whether the neutrino is a Dirac or a Majorana particle. The other question is about the absolute scale of neutrino mass. Neutrinoless double beta decay is the only practical way to answer the first question providing one of the most sensitive probes we have for physics beyond the Standard Model. It also well may be the only way to answer the second question in a laboratory environment. In this talk the motivation, present status and future plans of the search for neutrinoless double beta decay will be reviewed. I will also discuss the recent controversial evidence for the observation of this process with a Ge-detector. Particular attention will be paid to the NEMO experiment currently taking data in which the UK is actively participating and its possible successor SuperNEMO.

17 Nov. L. Roszkowski:
After a general introduction to the dark matter problem and a brief review of well-motivated particle candidates for resolving it, I will focus on the prospects for detecting the neutralino. I will next discuss alternative supersymmetric candidates and ways of testing them in experiment.

24 Nov. D. Miller:
If R-parity conserving supersymmetry exits below the Tev-scale, newparticles will be produced and decay in cascades at the LHC. The lightest supersymmetric particle will escape the detectors, thereby complicating the full reconstruction of the decay chains. In this talk, I expand on existing methods for determining the masses of the particles in the cascade from endpoints of kinematical distributions.

1 Dec. M. Dasgupta:
We briefly review the current understanding of QCD dynamics at all orders, by examining the role of multiple soft and collinear gluon radiation included through resummations at next-to-leading log accuracy for various observables in different collider processes. Special emphasis is given to recent computations involving more than 2 hard jets (crucial for LHC physics) and the role of wide-angle soft radiation.
Notes:
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