Search for single production of vector-like quarks decaying into W(ℓν)b in pp collisions at SQUARE ROOTs = 13 TeV with the ATLAS detector

Abstract

A search for single production of a vector-like quark Q, which could be either asinglet T, with charge 23, or a Y from a (T,B, Y ) triplet, with charge -43, is performed usingdata from proton-proton collisions at a centre-of-mass energy of 13TeV. The data correspondto the full integrated luminosity of 140 fb-1 recorded with the ATLAS detector during Run 2of the Large Hadron Collider. The analysis targets Q RIGHTWARDS ARROW Wb decays where the W bosondecays leptonically. The data are found to be consistent with the expected Standard Modelbackground, so upper limits are set on the cross-section times branching ratio, and on thecoupling of the Q to the Standard Model sector for these two benchmark models. Effects ofinterference with the Standard Model background are taken into account. For the singletT, the 95% confidence level limit on the coupling strength κ ranges between 0.22 and 0.52for masses from 1150 to 2300 GeV. For the (T,B, Y ) triplet, the limits on κ vary from 0.14 to 0.46 for masses from 1150 to 2600 GeV.