Eur. Phys. J. Plus (2020) 135: 339
https://doi.org/10.1140/epjp/s13360-020-00346-3

Regular Article

Study of interference effects in the search for flavour-changing neutral current interactions involving the top quark and a photon or a Z boson at the LHC

¹ Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Universidade do Minho, Braga, Portugal
² Departamento de Física, Escola de Ciências, Universidade do Minho, Braga, Portugal
³ Technische Universität Dortmund, Dortmund, Germany

^* e-mail: johannes.erdmann@tu-dortmund.de

Received: 18 September 2019
Accepted: 17 March 2020
Published online: 30 March 2020

Abstract

Flavour-changing neutral-current interactions of the top quark can be searched for in top-quark pair production with one top quark decaying to an up-type quark and a neutral boson, and they can be searched for in the single production of a top quark in association with such a boson. Both processes interfere if an additional up-type quark is produced in the case of single production. The impact of these interference effects on searches for flavour-changing neutral currents at the LHC is studied for the case where the neutral boson is a photon or a Z boson. Interference effects are found to be smaller than variations of the renormalisation and factorisation scales.