We study the consequences of adding to the standard model a left-right-symmetric, neutral singlet with a large Δ$I_W$=0 mass. This particle mixes with the standard neutrinos by virtue of the coupling to the conventional Higgs doublet. We investigate the effects of both Dirac and Majorana mass mixing on the rare low-energy process μ→eγ and on the decay of the W and Z. Significant and interesting effects on these latter decays can occur without violating the existing limit on the μ→eγ decay rate.

• Received 11 March 1985

DOI:https://doi.org/10.1103/PhysRevD.32.1186