Electric dipole moments and b-$\tau$ unification in the presence of an   intermediate scale in SUSY grand unification
  We show that an intermediate gauge symmetry breaking scale can be a significant source of electric dipole moments for the electron and neutron in supersymmetric grand unified theories. New phases, similar to that of the CKM matrix, appear which do not arise from the supersymmetry (SUSY) breaking operators. To illustrate, we choose some grand unified SUSY models having an intermediate gauge symmetry breaking scale with some attractive features. We also show how well the $b-\tau$ unification hypothesis works in this class of models. 
N. G. Deshpande, B. Dutta and E. Keith