A study of the charged scalar in the Zee model

An extension of the Zee model involving a light right handed neutrino, νR is considered. We update constraints on couplings between the bilepton scalar, the active neutrinos, νR and the charged leptons. We find that the most stringent constraint currently comes from measurements limiting the width of the decay μ→e γ. These are used to predict the upper bound on violation of lepton universality in W boson decays.