On the doublet/triplet splitting and intermediate mass scales in locally supersymmetric SO(10)

Abstract

In the light of the doublet/triplet splitting, the possibilities for an intermediate mass scale in locally supersymmetric SO(10) are analysed. It is found that the subgroup SU(4) c × SU(2) L × SU(2) R and more generally left-right symmetric models are unlikely to survive as intermediate symmetries since they imply too large values of the weak mixing angle. An alternative model using the subgroup SU(3) c × U(1) L × U(1) R is discussed. Requirements from global SUSY preservation impose an extra constraint and predictions for the grand unification and the intermediate masses are obtained at M X ≈ 6 × 10 15 GeV and M I ≈ 10 12 GeV.