Key points are not available for this paper at this time.
A combination of searches for the single production of vector-like top quarks (T) is presented. These analyses are based on proton-proton collisions at s=13 TeV recorded in 2015-2018 with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb^-1. The T-quark decay modes considered in this combination are into a top quark and either a Standard Model Higgs boson or a Z boson (T Ht and T Zt). The individual searches used in the combination are differentiated by the number of leptons (e, ) in the final state. The observed data are found to be in good agreement with the Standard Model background prediction. Interpretations are provided for a range of masses and couplings of the vector-like top quark for benchmark models and generalized representations in terms of 95% confidence level limits. For a benchmark signal prediction of a vector-like top quark SU2 singlet with electroweak coupling, , of 0. 5, masses below 2. 1 TeV are excluded, resulting in the most restrictive limits to date.
Aad et al. (Fri,) studied this question.