Single top quark production as a probe of anomalous tqγ and tqZ couplings at the FCC-ee

In this paper, a detailed study to probe the top quark Flavour-Changing Neutral Currents (FCNC) tq gamma and tqZ at the future e(-)e(+) collider FCC-ee in two different center-of-mass energies of 240 and 350 GeV is presented. Aset of useful variables are proposed and used in a multivariate technique to separate signal e(-)e(+) -> Z/gamma -> t (q) over bar (t (q) over bar) from Standard Model background processes. The study includes a fast detector simulation based on the DELPHES package to consider the detector effects. The upper limits on the FCNC branching ratios at 95% confidence level (CL) in terms of the integrated luminosity are presented. It is shown that with 300 fb(-1) of integrated luminosity of data, FCC-ee would be able to exclude the effective coupling strengths above O(10(-4) - 10(-5)) which is corresponding to branching fraction of O(0.01 - 0.001)%. We show that moving to a high-luminosity regime leads to a significant improvement on the upper bounds on the top quark FCNC couplings to a photon or a Zboson. (C) 2017 The Author(s). Published by Elsevier B.V.