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T: Fachverband Teilchenphysik
T 39: Top-Quark: Eigenschaften 3
T 39.1: Talk
Wednesday, February 29, 2012, 16:45–17:00, ZHG 105
Study of the Inclusive t t γ Cross Section at √s = 7 TeV with the CMS Experiment — Martina Davids, Heiko Geenen, Wael Haj Ahmad, Felix Höhle, Yvonne Küssel, Oliver Pooth, Achim Stahl, •Heiner Tholen, and Marc Zöller — III. Physikalisches Institut; RWTH Aachen
The top quark pair production with an associated photon in the final state is investigated to examine the electro-magnetic top quark coupling. With respect to Standard Model predictions, an additional contribution in the absolute scale of σtt γ / σtt or a deviation in the shape of the photon energy spectrum would indicate modifications in the t t γ vertex and therefore reveal new physics. A Monte-Carlo bench mark study has been performed using the generator tools WHIZARD and GoSam, providing LO and NLO calculations. We implement a cut based event selection to focus on top pair events in the muon+jets channel. On top of this preselection, t t γ candidates are identified by requiring a well isolated, high energy photon and additional mass constraints. In first approach, the ratio σtt γ, incl. / σtt is estimated and compared to data collected with the CMS detector at LHC.