Breaking of conservations laws induced by magnetic monopoles in the Rubakov-Callan model

Abstract

We have explored further implications of the model of Rubakov and Callan for a gauge theory with massless fermion isodoublets in the presence of a 't Hooft-Polyakov monopole. In a world with only one left-handed isodoublet, the fermion field is found to have a nonzero vacuum expectation value. We have studied a model with two doublets and find that there exist condensates, some of which break both chirality and charge (and color) conservation, and some others conserve chirality but break charge conservation. Unlike the proton-decay catalysis, these effects depend explicitly on the monopole size and are large only in the neighborhood of a monopole. Their existence is shown to be a necessary consequence of the boundary condition in the model.