SUPERSYMMETRY, R-PARITY BREAKING AND THE NEUTRINO MAGNETIC-MOMENT

We show that supersymmetric theories with R-parity breaking naturally give rise to significant neutrino magnetic moments. In the minimal supersymmetric standard model the transition magnetic moment mu-VeV-mu can be as large as 10(-13) mu-B (mu-B is the Bohr magneton). By requiring an SU (2)H horizontal symmetry of the lagrangian in the Yukawa-less limit, mu-VeV-mu may be one order of magnitude larger. In this case the main naturalness constraint on the maximum mu-VeVe-mu attainable is the electron mass value rather than the bound on the o neutrino mass itself.