SIR Physics Investigation Abstract
USING A DILEPTON ANALYSIS TO DETECT SUPERSYMMETRY AT CDF AT FERMILAB
Presenter:
Susan Dittmer, Illinois Mathematics and Science Academy
Advisor:
Dr. Jane Nachtman, Fermi National Accelerator Laboratory
Abstract:
Supersymmetry (SUSY) is a leading option for an extension of the Standard Model (SM), and theoretically provides solutions some of the most important questions in physics. However, no experimental evidence has been produced for SUSY's existence, mainly because the decays of SUSY particles are often obscured by SM background. To look for SUSY, a dilepton analysis was performed to isolate possible SUSY decays from Drell-Yan processes, the main source of SM background. Cuts were first developed to extract dimuon events from the dilepton sample, thus concentrating on dimuon production. These cuts were applied to a sample of known muons to verify a high cut efficiency. Dimuon events were also selected from Drell-Yan and SUSY datasets, which had been created using Monte Carlo simulation. Graphs of the mass and sum of transverse momentum were compared for the Drell-Yan, SUSY and CDF datasets to see what was predicted by SUSY and Drell-Yan versus what was actually seen in the detector. To enhance the sensitivity to SUSY, the ratio of dimuon events in the low mass region to those in the Z peak was calculated and used to exclude certain areas. If a statistically significant number of events occurred in a SUSY dominated region outside of the predicted number of Drell-Yan events, this would be taken as evidence for supersymmetry.