Must the new heavy lepton have it's own neutrino?

Abstract We consider a minimal gauge theory of leptons, including only e, μ, the newly found charged lepton L and two massless two-component neutrinos. The model implies muon number non conservation. The present limit on μ +Nucleus→e+Nucleus leads to a branching ratio for μ →e γ not larger than 1.7 × 10 −12 . Striking violations of μ −e universality in L decays are predicted.