Fermion Masses in Susy Guts

We discuss the fermion mass problem in SUSY GUTs, including such ideas as texture zeroes, and Georgi-Jarlskog textures. We focus on a specific supersymmetric model based on the gauge group SU(4)⊗SU(2)L ⊗SU(2)R. In this model the gauge group is broken to that of the standard model at 10 GeV, and supersymmetry is broken at low-energy. The model may be regarded as a “surrogate SUSY GUT”, and has several advantages over the SU(5) and SO(10) SUSY GUTs, such as the absence of the doublet-triplet splitting problem, and a simpler Higgs sector which does not involve any large Higgs representations. The model predicts full quadruple Yukawa unification (top-bottom-tau-tau neutrino), leading to the prediction of large top mass and tan β. An operator analysis leads to schemes where the strange and down mass are predicted, and |Vub| > 0.004. Invited talk at the International Workshop on Elementary Particle Physics: Present and Future, Valencia 1995. Address after 1 October 1995: Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX. Talk presented by S. F. King.