Rare muon decays, heavy leptons, andCPviolation

We generalize and elaborate a model recently proposed by Cheng and Li. It is characterized by the breakdown of separate conservation laws for e and μ lepton types and allows for such processes as μ→e+γ, μ→3e. Our generalization incorporates the singly charged heavy lepton discovered in e⁺e^- colliding-beam experiments, and it opens up the possibility of introducing CP-violating effects in lepton reactions. We analyze the μ→3e decay process, both with respect to rate (relative to μ→e+γ and spectrum, including CP-violating correlations. Other physically interesting features are also discussed for the generalized scheme: neutrino "sharing" and off-diagonal neutral-current effects.