Caltech Library System

About | Browse | Search | Caltech Student Instructions

Type of Document	Dissertation
Author	Xia, Lei
Author's Email Address	Lei.Xia AT cern.ch
URN	etd-11052002-223015
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-11052002-223015
Title	Search for scalar leptons at LEP with the L3 detector
Degree	PhD
Option	Physics
Advisory Committee	Advisor Name Title Harvey Newman Committee Chair Alan Weinstein Committee Member Bradley Filippone Committee Member Mark Wise Committee Member
Keywords	supersymmetry SUSY L3 LEP scalar lepton
Date of Defense	2002-11-01
Availability	unrestricted
Abstract In this thesis, I present a search for scalar leptons in e+e- annihilation using the L3 detector at LEP. Data collected in 1999 and 2000, at center-of-mass energies between 192 GeV and 208 GeV, was used in this analysis. This work covered the scalar lepton searches in both SUGRA and GMSB models. To achieve this analysis, a parametrized selection was developed to handle the different event signatures in SUGRA models. Improvement of the L3 simulation and reconstruction program packages was carried out so that one can simulated the scalar leptons in GMSB models correctly. The simulation of the L3 Time Expansion Chamber (TEC) dE/dx measurement was rewritten to facilitate the analysis for a stable slepton signal, which is relevant in some parts of the parameter space in GMSB models. In this analysis, we didn't abserve any significant indication of scalar lepton production of any type. We achieved the following mass exclusion limits for scalar leptons in SUGRA models, for large dM: M(scalar e) > 97 GeV (expected 97 GeV) M(scalar mu) > 86 GeV (expected 86 GeV) M(scalar tau) > 78 GeV (expected 79 GeV) We achieved the following lifetime independent mass exclusion limits for scalar taus in GMSB modles: M(scalar tau) > 80 GeV (expected 79 GeV)
Files	Filename       Size       Approximate Download Time (Hours:Minutes:Seconds)     28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access    thesis.pdf 13.55 Mb 01:02:43 00:32:15 00:28:13 00:14:06 00:01:12