Overview of searches for single production of vector-like top and bottom quarks with the ATLAS experiment at 13 TeV

Abstract: Vector-like quarks (VLQ) that couple preferentially to third-generation Standard Model (SM) quarks are a well-motivated extension of the SM, which could solve in particular the hierarchy problem. While VLQs can be produced in pairs via the strong interaction at the LHC, the cross section for single production may be larger than the pair production cross section for VLQ masses above the current exclusion limits. An overview of the searches for the single production of VLQs at the ATLAS experiment that use data taken at a centre-of-mass energy of 13 TeV, corresponding to up to 79.8 fb$^{-1}$, is presented. Vector-like top quarks are searched for in the decay channel $T\rightarrow Wb$ and in the decay channel $T\rightarrow Zt$ with the $Z$ boson decaying to two charged leptons. Vector-like bottom quarks are searched for in the decay channel $B\rightarrow Hb$ with the Higgs boson decaying to two photons. No significant excess over the SM prediction is found and 95% CL exclusion limits are set on the single production of VLQs as a function of their mass and coupling to SM quarks.