Cosmic Strings in Realistic Particle Physics Theories and Baryogensis

Abstract

Grand unified theories can admit cosmic strings with fermion zero modes. Such zero modes result in the string being current-carrying and the formation of stable remnants, vortons. However, the string zero modes do not automaticall survive subsequent phase transitions. In this case the vortons dissipate. It is possible that the dissipating cosmic vortons create the observed baryon asymmetry of the universe. We show that fermion zero modes are an automatic consequence cosmic strings in supersymmetric theories. Since supersymmetry is not observed in nature, we consider possible supersymmetry breaking terms. Some of these terms result in the zero modes being destroyed. We calculate the baryon asymmetry generated by the consequent dissipating cosmic vortons. If the supersymmtry breaking scale is high enough, then the dissipating cosmic vortons could account for the observed baryon asymmetry.