A Search for tt ̄ Resonances in the Lepton Plus Jets Channel from Proton-Proton Collisions at √s = 8 TeV with the ATLAS Detector

• Main Author: Pollard, Chris
• Other Authors: Kotwal, Ashutosh
• Published: 2014
• Subjects: Physics
• Online Access: http://hdl.handle.net/10161/9114

<p>A search for the resonant production of top quark pairs in</p><p>proton-proton collisions at a center-of-mass energy of 8~TeV is</p><p>presented.</p><p>The Large Hadron Collider delivered 14 inverse femtobarns of collision</p><p>data which were collected by the ATLAS detector.</p><p>The lepton plus jets final state is used, and the top pair invariant</p><p>mass spectrum is probed for local excesses above the Standard Model</p><p>background prediction.</p><p>No evidence for resonant top pair production is found.</p><p>95\% credibility limits are set on the cross section times branching</p><p>ratio of two signal benchmarks.</p><p>A narrow leptophobic topcolor $Z^\prime$ boson decaying to top quark</p><p>pairs and the Kaluza-Klein excitation of the gluon in a</p><p>Randall-Sundrum model are excluded for masses below 1.8 and 2.0~TeV,</p><p>respectively.</p><p>The expected sensitivity to new physics at ATLAS with proton-proton</p><p>collisions delivered by a High Luminosity Large Hadron Collider is</p><p>also presented.</p><p>The feasibility of analyses studying vector boson scattering, exotic</p><p>resonances, and an extended Higgs sector with up to 3000 inverse</p><p>femtobarns of integrated luminosity is investigated based on the fast</p><p>simulation of proton-proton collisions at a center-of-mass energy of</p><p>14~TeV.</p> === Dissertation