More on R-parity- and lepton-family-number-violating couplings from muon(ium) conversion, and tau and pi(0) decays

Abstract

We present a new class of constraints to the lepton-family-number- and R-parity-violating couplings from muonium conversion mu(-) + Ti-48(22) --> e(-) + Ti-48(22), a class of tau decays tau --> l+ (light meson) with l = mu or e, and J/psi and pi(0) decays into a lepton pair. We find that mu(-) + Ti-48(22) --> e(-) + Ti-48(22) provides one of the strongest at constraints along with Delta m(K), Delta m(B), mu --> e gamma, and the neutrinoless double beta decay. The search for these lepton family-number-violating decays forbidden in the standard model is clearly warranted in various low-energy experiments such as tau-charm factories and PSI. etc.