RENORMALIZATION-GROUP-INDUCED NEUTRINO MASS IN SUPERSYMMETRY WITHOUT R-PARITY

We study supersymmetric models without R parity and with universal sof t supersymmetry-breaking terms. We show that as a result of the renorm alization group Row of the parameters, a misalignment between the dire ctions in field space of the down-type Higgs vacuum expectation value v(d) and of the mu term is always generated. This misalignment induces a mixing between the neutrinos and the neutralinos, resulting in one massive neutrino. By means of a simple approximate analytical expressi on, we study the dependence on the different parameters that contribut e to the misalignment and to m(v). In large part of the parameter spac e this effect dominates over the standard one-loop contributions to m( v); we estimate 1 MeV less than or similar to m(v) less than or simila r to 1 GeV. Laboratory, cosmological, and astrophysical constraints im ply m(v) less than or similar to 100 eV. To be phenomenologically viab le, these models must be supplemented with some additional mechanism t o ensure approximate alignment and to suppress m(v).