FERMION MASS TEXTURES IN AN M-INSPIRED FLIPPED SU(5) MODEL DERIVED FROM STRING

We are inspired by the facts that M theory may reconcile the supersymm etric GUT scale with that of quantum gravity, and that it provides new avenues for low-energy supersymmetry breaking, to re-examine a flippe d SU(5) model that has been derived from string and may possess an ele vation to a fully-fledged M-phenomenological model. Using a complete a nalysis of all superpotential terms through the sixth order, we explor e in this model a new flat potential direction that provides a pair of light Higgs doublets, yields realistic textures for the fermion mass matrices, and is free of R-violating interactions and dimension-five p roton decay operators. (C) 1998 Elsevier Science B.V. All rights reser ved.