Search for a W Boson Decaying to a Lepton and a Neutrino in Proton-proton Collisions at

A search for a new high-mass resonance decaying to a τ lepton and a neutrino is reported. The analysis uses proton-proton collision data collected by the CMS experiment at the LHC at $\sqrt{s}=13\phantom{\rule{0.2em}{0ex}}\text{TeV}$, corresponding to an integrated luminosity of 35.9$\phantom{\rule{0.2em}{0ex}}{\text{fb}}^{-1}$. The search utilizes hadronically decaying τ leptons. No excess in the event yield is observed at high transverse masses of the τ and missing transverse momentum. An interpretation of results within the sequential standard model excludes ${W}^{\prime }$ boson masses below 4.0 TeV at 95% confidence level. Existing limits are also improved on models in which the ${W}^{\prime }$ boson decays preferentially to fermions of the third generation. Heavy ${W}^{\prime }$ bosons with masses less than 1.7–3.9 TeV, depending on the coupling in the non-universal G(221) model, are excluded at 95% confidence level. These are the most stringent limits on this model to date.