Transient vacuum structures and baryon asymmetry of the Universe

Sphalerons in the Standard Model suggest the possibility that all the baryon asymmetry of the Universe could have been created at the electroweak scale. This relies on occurrence of bubble walls during the phase transition. In this talk we focus on an alternative mechanism for occurrence of nontrivial transient background configurations. We show that the domain walls accompanying the phase transition in the Left-Right symmetric model provide sufficient conditions for baryogenesis. It is then possible to derive conditions relating the scale of L-R breaking and the light neutrino masses suggested by the neutrino data.