Type of Document	Dissertation
Author	Gleyzer, Sergei V.
Author's Email Address	svg04d@fsu.edu
URN	etd-07092011-152458
Title	The Search For The Dark Matter Signature In The Lepton Jet Final State At Sqrt(s) = 7 TeV
Degree	Doctor of Philosophy
Department	Physics, Department of
Advisory Committee	Advisor Name Title Vasken Hagopian Committee Chair Bernd Berg Committee Member Grigory Rogachev Committee Member Harrison Prosper Committee Member Sanford Safron University Representative
Keywords	Compact Muon Solenoid High Energy Physics Particle Large hagroun Collider
Date of Defense	2011-05-10
Availability	unrestricted
Abstract The Large Hadron Collider is pushing high energy physics in to a brand new territory. This extraordinary era may bring discoveries of unprecedented magnitude, delivering validation or extreme dissappointment to the physics theories of the previous decades. By colliding particles at more than 3.5 times the center of mass energy of the Tevatron accelerator at the Fermilab National Accelerator Laboratory, the CERN Large Hadron Collider aims to produce particles in the mass range above those that are already known. At the same time, there are exciting possibilities for new physics in the low-mass range that may have gone unnoticed until now. An example of this is a GeV-scale dark sector with a colorful spectrum of new particles. This physics model produces unique signatures of collimated leptons at the Large Hadron Collider energies. In the first part of this work, we describe the interesting astrophysical evidence that motivates a search for lepton jets and focus our attention on a minimal supersymmetric standard model with a GeV-scale dark sector that produces this exciting signature. In the next part of the thesis, we describe a search using the Compact Muon Solenoid (CMS) detector for evidence of dark matter in events containing muonic lepton-jets produced in 7 TeV proton-proton collisions at the Large Hadron Collider. We employ a novel lepton jet algorithm and find no evidence of an excess of such events with respect to the rate predicted by the Standard Model and interpret the null result in terms of a recently developed supersymmetric theory of dark matter. In doing so, we severely constrain the theoretical model and its parameters with the actual data from the Large Hadron Collider. In addition, we report the first observation of double J/Psi production, a new physical process discovery at the next energy frontier.
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