A new mechanism for baryogenesis in low energy supersymmetry breaking models

Abstract

A generic prediction of models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge interactions is the existence of superconducting cosmic strings which carry baryon number. In this paper we propose a novel mechanism for the generation of the baryon asymmetry which takes place at temperatures much lower than the weak scale. Superconducting strings act like “bags” containing the baryon charge and protect it from sphaleron wash-out throughout the evolution of the Universe, until baryon number violating processes become harmless. The superconducting strings are out of equilibrium configurations which admit baryon number violating processes such that all of the Sakharov criteria for baryogenesis are satisfied. Our mechanism is efficient even if the electroweak phase transition in the MSSM is of second order and therefore does not impose any upper bound on the mass of the Higgs boson.