Radiative mechanisms for the 17 keV neutrino and the MSW mass scale

Abstract

We present the simplest SU (2) ⊗ U (1) models with a spontaneously broken global U (1)-symmetry which naturally account for the 17 keV anomalies in beta decays and for the explanation of the solar neutrino deficit through resonant ν e conversions into an ultralight sterile neutrino. Two scales of neutrino masses arise naturally from radiative corrections in one- and two-loop levels associated to the exchange of new Higgs bosons. One of the models predicts the possibility of having exotic rare decay modes of the tau lepton, τ→ e+ J where J is the majoron, τ→ e+ γ and τ→3 e with branching ratios accessible to experiment.