The μ−→e−+γ decay rate is evaluated in the framework of the triplet model of Gelmini and Roncadelli. It is shown that the contributions of the charged Higgs sector are larger than the ordinary gauge ones by at least twenty-four orders of magnitude. We obtain a lower limit for the ratio R>3.6×10−12|[m^2]νeμ|^2 KeV^4, where [m^2ν ]eμ is the relevant off-diagonal leptonic mixing. The experimental upper bound to the process is used to impose contraints over these mixing parameters. Similar reasoning is used for the τ−→μ−γ and τ−→e−γ processes.

This work has been supported in part by Comisión Asesora de Investigación Cientffica y Técnica, Spain. One of us (A.S.) is indebted to Ministerio de Educación y Ciencia for a fellowship.

6 páginas, 2 figuras.

Peer reviewed