In models with flavor symmetries in the leptonic sector leptogenesis can take
place in a very different way compared to the standard leptogenesis scenario.
We study the generation of a B−L asymmetry in these kind of models in the
flavor symmetric phase pointing out that successful leptogenesis requires (i)
the right-handed neutrinos to lie in different representations of the flavor
group; (ii) the flavons to be lighter at least that one of the right-handed
neutrino representations. When these conditions are satisfied leptogenesis
proceeds due to new contributions to the CP violating asymmetry and -depending
on the specific model- in several stages. We demonstrate the validity of these
arguments by studying in detail the generation of the B−L asymmetry in a
scenario of a concrete A4 flavor model realization.Comment: 25 pages, 7 figures; version 2: A few clarifications added. Version
matches publication in JHE
