A new mechanism for baryogenesis in low energy supersymmetry breaking models

A generic prediction of models where supersymmetry is broken at scales with in a few orders of magnitude of the weak scale and is fed down to the obser vable sector by gauge interactions is the existence of superconducting cosm ic strings which carry baryon number. In this paper we propose a novel mech anism for the generation of the baryon asymmetry which takes place at tempe ratures much lower than the weak scale. Superconducting strings act like "b ags" containing the baryon charge and protect it from sphaleron wash-out th roughout the evolution of the Universe, until baryon number violating proce sses become harmless. The superconducting strings are out of equilibrium co nfigurations which admit baryon number violating processes such that all of the Sakharov criteria for baryogenesis are satisfied. Our mechanism is eff icient even if the electroweak phase transition in the MSSM is of second or der and therefore does not impose any upper bound on the mass of the Higgs boson. (C) 1999 Elsevier Science B.V. All rights reserved.