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T: Fachverband Teilchenphysik
T 46: Top: Boosted b-tagging, single top
T 46.9: Vortrag
Dienstag, 10. März 2015, 18:45–19:00, L.09.31 (HS 11)
Single Top-Quark Production through Flavour Changing Neutral Currents — •Ozan Arslan1, Ian C. Brock1, and Dominic Hirshbuehl2 for the ATLAS collaboration — 1University of Bonn, Bonn, Germany — 2University of Wuppertal, Wuppertal, Germany
Flavour Changing Neutral Current (FCNC) processes are highly suppressed in the Standard Model due to Glashow-Iliopoulos-Maiani (GIM) mechanism. However, in some extensions of the Standard Model such as supersymmetry (SUSY) and the 2-Higgs doublet model, the FCNC contributes at tree level, enhancing the branching ratio significantly. The FCNC are searched for in single top-quark production where a u(c)-quark interacts with a gluon, producing a single top-quark with no associated quark production. The data collected by the ATLAS detector during year 2012 is used with a center-of-mass energy of √s=8 TeV, corresponding to an integrated luminosity of ∼ 20 fb−1. The candidate signal events are selected by requiring one lepton, muon or electron, missing transverse momentum and exactly one jet originating from a b-quark in the final state. The separation between the signal and background events is enhanced by using neural network algorithms. The cross section upper limit at 95% C.L. is calculated following frequentist statistical approach using a binned likelihood method calculated from the full neural network output.