Leptogenesis in natural low-scale seesaw mechanisms
  We explore the hypothesis of having an approximate lepton number conservation
as a way to achieve a successful leptogenesis in low-scale seesaw mechanisms.
The smallness of the active neutrino masses, as well as a strong degeneracy in
the mass spectrum of the heavy sterile states, are both consequence of the
assumed approximate symmetry. We propose a minimal extension of the Standard
Model in order to implement the idea, and perform an analytical and numerical
study to determine the viable solutions in the model and the testability of
this leptogenesis scenario in future experiments.
