SpontaneousR-parity breaking in supersymmetric models

Abstract

We investigate a mechanism for spontaneous $R$-parity breaking in a class of extensions of the minimal supersymmetric standard model with an extra Abelian gauge symmetry which is a linear combination of $B\ensuremath{-}L$ and weak hypercharge. Both $U(1{)}_{X}$ and $R$-parity are broken by the vacuum expectation value of the right-handed sneutrinos, which is proportional to the soft supersymmetric masses. In these models the mechanism for spontaneous $R$-parity violation can be realized even with positive soft masses. In this context one has a realistic mechanism for generating neutrino masses as well as a realistic spectrum. We briefly discuss the possible collider signals which could be used to test the theory, the contributions to proton decay, and the possibility of a gravitino as a dark matter candidate.