Constraints on the baryogenesis scale from neutrino masses

Using the interplay between anomalous electroweak processes at very high temperatures and B-L violating interactions, we derive bounds, related to neutrino masses, on the scale at which a B-L asymmetry must have been produced in the early universe. We consider in particular, the out-of-equilibrium decays of heavy right-handed neutrinos, as well as the effects of B-L violation in other extensions of the standard model.