Lepton flavor violating decaysτ→l¯llandμ→eγin the Higgs triplet model

Abstract

Singly and doubly charged Higgs bosons in the Higgs triplet model mediate the lepton flavor violating (LFV) decays {tau}{yields}lll and {mu}{yields}e{gamma}. The lepton flavor violating decay rates are proportional to products of two triplet Yukawa couplings (h{sub ij}) which can be expressed in terms of the parameters of the neutrino mass matrix and an unknown triplet vacuum expectation value. We determine the parameter space of the neutrino mass matrix in which a signal for {tau}{yields}lll and/or {mu}{yields}e{gamma} is possible at ongoing and planned experiments. The conditions for respecting the stringent upper limit for {mu}{yields}eee are studied in detail, with emphasis given to the possibility of |h{sub ee}|{approx_equal}0, which can only be realized if Majorana phases are present.