Mainz 2014 – scientific programme

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T: Fachverband Teilchenphysik

T 61: Top-Quarks: Single Top

T 61.8: Talk

Tuesday, March 25, 2014, 18:30–18:45, P102

Single Top Quark Production through Flavour Changing Neutral Currents — •Ozan Arslan and Ian C. Brock — Physikalisches Institute, Bonn, Germany

Flavour Changing Neutral Current (FCNC) processes are highly suppressed in the Standard Model due to the Glashow-Iliopoulos-Maiani (GIM) mechanism. However, in some extensions of the Standard Model such as supersymmetry (SUSY) and the 2-Higgs doublet model, FCNC contribute at tree level, enhancing the branching ratio significantly. FCNC are searched for 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 2012 are used with a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of ∼20 fb⁻¹. The candidate signal events are selected by requiring a muon or an 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 Bayesian statistical approach using a binned likelihood method calculated from the full neural network output.