Search for High-Mass Resonant ttbar Production in Electron+Jets Events in 7 TeV pp Collisions
thesisposted on 28.06.2013, 00:00 by Samvel Khalatian
In this thesis we present a model-independent search for the production of heavy resonances with mass greater than 1 TeV decaying to top quark pairs. Using data samples corresponding to 5.0 fb−1 of integrated luminosity of pp collision data recorded with the Compact Muon Solenoid ￼experiment in 2011 at sqrt(s) = 7 TeV, we select events containing one electron and at least two jets and look for excess above Standard Model background prediction in the top quark pair invariant mass spectrum. The high transverse momenta of the top quarks originating from such decays result in an event topology which requires a dedicated event selection and reconstruction of the invariant top quark pair mass. We use a Chi2 method in the reconstruction and selection of top quark pairs and apply b-tagging to improve sensitivity. In the absence of evidence for a signal, we evaluate 95% C.L. upper limits on sigma(pp->Z'->ttbar)*BR as a function of the invariant mass of the resonance.