Aachen 2019 – scientific programme

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T: Fachverband Teilchenphysik

T 35: Top-Physik I

T 35.9: Talk

Tuesday, March 26, 2019, 18:00–18:15, S10

Search for tqH FCNC couplings at the ATLAS experiment — •Oliver Thielmann, Wolfgang Wagner, Geoffrey Gilles, and Arunika Sahu — Bergische Universität Wuppertal (BUW)

Processes involving flavour-changing neutral currents (FCNC) are highly suppressed in the top-quark sector and an observation of such processes would signal physics beyond the Standard Model. An important example are the ctH and utH FCNC vertices which lead to the production process pp ->tH and the decay t -> c(u) H in t tbar events. Different reconstruction techniques of the associated final states are compared. Neural networks are employed to separate signal and background events in the signal region. A potential signal is searched for by means of a profile likelihood fit to the neural network discriminants. The sensitivity of the search is quantified in terms of upper limits of the ctH and utH couplings in the context of an Effective Field Theory.