Search for single production of vector-like quarks decaying into W(l nu)b in pp collisions at root(s) = 13 TeV with the ATLAS detector

A search for single production of a vector-like quark Q, which could be either a singlet T, with charge 2/3, or a Y from a (T, B, Y) triplet, with charge -4/3, is performed using data from proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to the full integrated luminosity of 140 fb-1 recorded with the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis targets Q -> Wb decays where the W boson decays leptonically. The data are found to be consistent with the expected Standard Model background, so upper limits are set on the cross-section times branching ratio, and on the coupling of the Q to the Standard Model sector for these two benchmark models. Effects of interference with the Standard Model background are taken into account. For the singlet T, the 95% confidence level limit on the coupling strength kappa ranges between 0.22 and 0.52 for masses from 1150 to 2300 GeV. For the (T, B, Y) triplet, the limits on kappa vary from 0.14 to 0.46 for masses from 1150 to 2600 GeV.