Author: Alexandre Zabi

Publisher:

Published: 2004

Total Pages: 238

ISBN-13:

The D0 experiment, located at the Fermilab National Accelerator Laboratory in the US, is used to study proton-anti-proton collisions at a center of mass energy of 1.96 TeV. The experiment's data acquisition system is based on a sophisticated trigger system used to select potentially interesting events. The Level 2 Silicon Track Trigger (L2STT) is part of the trigger system that provides precise reconstruction of charged particle tracks allowing the selection of events that contain the decays of long lived particles. For example, such particles appear in the decay of the Higgs boson into a pair of bottom quarks. The design of the L2STT preprocessor has greatly benefited from recent advances in electronics technology. The preprocessor has been recently installed and will be used to further optimize the triggering strategy of the experiment. Leptoquarks would mediate hypothetical new interactions between the quarks and leptons of the Standard Model. The existence of such particles would be evidence for physics beyond that model. In this thesis, a direct search for leptoquarks is performed in the jets and missing transverse energy final state. For this analysis, a trigger had to be developed along with a tool to precisely determine its efficiency. An analysis of events exhibiting the acoplanar jets topology was performed on a data sample corresponding to an integrated luminosity of 85 pb{sup -1}. This analysis has resulted in the determination of an exclusion region on the possible masses of leptoquarks ranging from 85 GeV/c{sup 2} to 109 GeV/c{sup 2} at the 95% confidence level.