Constraints on baryon-nonconserving Yukawa couplings in a supersymmetric theory

Abstract

The 1-loop evolution of couplings in the minimal supersymmetric standard model, extended to include baryon nonconserving (B/) operators through explicit R-parity violation, is considered keeping only B/ superpotential terms involving the maximum possible number of third generation superfields. If all retained Yukawa couplings Y_i are required to remain in the perturbative domain (Y_i < 1) up to the scale of gauge group unification, upper bounds ensue on the magnitudes of the B/ coupling strengths at the supersymmetry-breaking scale, independent of the model of unification. They turn out to be similar to the corresponding fixed point values reached from a wide range of Y_i (including all Y_i greater than unity) at the unification scale. The coupled evolution of the top quark and B/ Yukawa couplings results in a reduction of the fixed point value of the former.