Search for vector-boson resonances decaying to a top quark and bottom quark in the lepton plus jets final state in pp collisions at √s = 13 TeV with the ATLAS detector

Abstract

A search for new charged massive gauge bosons, <i>W'</i>, is performed with the ATLAS detector at the LHC. Data were collected in proton–proton collisions at a center-of-mass energy of √s = 13 TeV and correspond to an integrated luminosity of 36.1 fb⁻¹. This analysis searches for <i>W'</i> bosons in the <i>W' → t ̄ b</i> decay channel in final states with an electron or muon plus jets. The search covers resonance masses between 0.5 and 5.0 TeV and considers right-handed <i>W'</i> bosons. No significant deviation from the Standard Model (SM) expectation is observed and upper limits are set on the <i>W' → t ̄ b</i> cross section times branching ratio and the <i>W'</i> boson effective couplings as a function of the <i>W'</i> boson mass. For right-handed <i>W'</i> bosons with coupling to the SM particles equal to the SM weak coupling constant, masses below 3.15 TeV are excluded at the 95% confidence level. This search is also combined with a previously published ATLAS result for <i>W' → t ̄ b</i> in the fully hadronic final state. Using the combined searches, right-handed W bosons with masses below 3.25 TeV are excluded at the 95% confidence level.