R_b in Supergravity Grand Unification with Non-universal Soft SUSY Breaking

Abstract

An analysis of supersymmetric contributions to R_b in supergravity grand unification with non-universal boundary conditions on soft SUSY breaking in the scalar sector is given. Effects on R_b of Planck scale corrections on gaugino masses are also analysed. It is found that there exist regions of the parameter space where positive corrections to R_b of size $\sim 1\sigma$ can be gotten. The region of the parameter space where enhancement of R_b occurs is identified. Prediction of the full sparticle spectrum for the maximal R_b case is given. The analysis has implications for the discovery of supersymmetric particles at colliders.