Fermion mass prediction from Infra-red fixed points

Abstract

We argue that in a wide class of theories the fermion and soft supersymmetry breaking mass structure is largely determined by the infra-red fixed point structure of the theory lying beyond the \smp We show how knowlege of the symmetries and multiplet content of this theory is sufficient to determine the infra-red structure, illustrating the idea for the case of a simple abelian family symetry. The resulting structure determines the fermion masses and mixing angles in terms of a restricted number of parameters.