Monopole-induced baryon number violation due to weak anomally

Abstract

Magnetic monopoles may catalyze baryon number violation due to the weak 't Hooft anomaly, even if the boundary conditions at the monopole core conserve baryon number. We show, by analyzing a simple toy model, that this effect is unsuppressed by any power of the monopole size, weak symmetry breaking scale, or coupling constant, provided the radius of the monopole core is smaller than Eg²/m_w², E being the energy of the external fermions, g the coupling constant of the SU(2)^weak group, and m_w the SU(2)^weak breaking scale. It is argued that this is a general feature of all monopoles (not necessarily 't Hooft-Polyakov monopoles). Possible suppression factors due to the presence of higher generation fermions are discussed.