Neutrino mass generation and singly charged leptonic exotics in WW events

Abstract

Current measurement of leptonic WW is significantly higher than the standard model prediction which may accommodate new physics signal that mimics the leptonic decaying W. We investigate a TeV neutrino mass generation model that predicts singly charged leptonic exotics. The collider signature of this model may mimic the leptonic WW search and evade all other searches. With introduction of new SU(2)L doublet leptons, singly charged exotic leptons L± decay into L±→ℓ±ϕ where ϕ is a light singlet scalar of O(MeV) that decays into neutrinos. Drell–Yan production of L+L−→ℓ+ℓ−+E̸T fits leptonic WW searches and L±L0→ℓ±+E̸T is completely buried in SM background. In the case of direct lepton from L-decay instead of secondary decay from leptonic τ±, we find the lower mass bound as 125 GeV of such exotic leptons that can be accommodated by the current measurements of WW searches at the LHC. To derive the upper bound, we employ both heavy Higgs boson search of di-lepton plus E̸T final state and leptonic W′ search of single lepton plus E̸T. Even though heavy Higgs is excluded between 260 and 640 GeV, we find LHC data can still accommodate L between 150 and 300 GeV after giving up the ηℓℓ cut. Using the single W′ search bound, we can obtain an approximate upper bound as 300 GeV.