ar X iv : h ep - p h / 97 02 44 2 v 1 2 7 Fe b 19 97 R b in Supergravity Grand Unification with Non - universal Soft SUSY Breaking

An analysis of supersymmetric contributions to Rb in supergravity grand unification with non-universal boundary conditions on soft SUSY breaking in the scalar sector is given. Effects on Rb 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 Rb of size ∼ 1σ can be gotten. The region of the parameter space where enhancement of Rb occurs is identified. Prediction of the full sparticle spectrum for the maximal Rb case is given. The analysis has implications for the discovery of supersymmetric particles at colliders. The Standard Model(SM) predicts a value of Rb of R b = 0.2159, mt = 175GeV (1) with δRb/δmt = −0.0002. The experimental value of Rb has been in a state of flux over the past couple of years. The experimental analyses in 1994-95 indicated Rb = 0.2208± 0.0024. However, more recently R b has drifted downwards, and currently, assuming the value of Rc at its SM value of Rc = 0.172, one finds [1]