Thesis Committee: Mark Kruse (Advisor), Seog Oh, Kate Scholberg, Stephen Teitsworth
In this study, we conduct preliminary steps necessary for developing an analysis of dilepton events in the frst ATLAS collision data. Using ATLAS Monte Carlo samples at √s = 10 TeV, we study the contributions of various Standard Model processes to the high-pT dilepton sample consisting of an electron and a muon of opposite charge. Our three main signal processes are tt¯, WW , and Z → ττ. The background processes that we examine are W + jets where a jets fakes a lepton, W + γ where the γ fakes an electron, WZ, and ZZ. The eµ events from each sample are plotted in the phase space of number of jets, Njets, versus missing transverse energy, ET, which provides a nice separation between the signal processes. For an event that lands at a given coordinate in the (Njets, ET) phase space, we estimate the probability that it came from a given process using the expected 2-D distributions of the processes considered. All findings are consistent with our qualitative expectations based upon the theoretical cross-sections for the different processes at >ATLAS at √s = 10 TeV. This analysis will be used to monitor the frst eµ events that are recorded by ATLAS as a means to evaluate their consistency with the Standard Model. Additionally, in an independent study, we assess the possibility of measuring the mean interaction length in the ATLAS Transition Radiation Tracker straws by examining a correlation found in both cosmic data and ATLAS Monte Carlo. While we conclude that this parameter cannot be determined using this method, the study nonetheless helps towards furthering our understanding of charge collection in the TRT.
Here is the thesis in PDF: Minot_thesis.pdf