Domain walls. II. Baryon-number generation

Domain walls present in the early universe due to a spontaneous breakdown of charge conjugation can leave behind net baryon number. $\mathrm{S}{\mathrm{U}}_R\mathrm{}\left(2\right)\mathrm{}$ instantons provide baryon nonconservation and the proton is effectively stable. Density perturbations (on scales large enough for galaxy formation) and monopole suppression can occur if walls dominate the energy density. Mechanisms for wall removal are discussed.