NEW MODELS OF GAUGE-MEDIATED AND GRAVITY-MEDIATED SUPERSYMMETRY BREAKING

We show that supersymmetry breaking in a class of theories with SU(N) x SU(N-2) gauge symmetry can be studied in a calculable a model. We us e the a model to show that the supersymmetry-breaking vacuum in these theories leaves a large subgroup of flavor symmetries intact, and to c alculate the masses of the low-lying states. By embedding the standard model gauge groups in the unbroken flavor symmetry group we construct a class of models in which supersymmetry breaking is communicated by both gravitational and gauge interactions. One distinguishing feature of these models is that the messenger fields, responsible for the gaug e-mediated communication of supersymmetry breaking, are an integral pa rt of the supersymmetry-breaking sector. We also show how, by lowering the scale that suppresses the nonrenormalizable operators, a class of purely gauge-mediated models with a combined supersymmetry-breaking-c um-messenger sector can be built. We briefly discuss the phenomenologi cal features of the models we construct.