Lepton number symmetry as a way to testable leptogenesis

Abstract

We propose a minimal and motivated extension of the Standard Model characterised by an approximate lepton number conservation, which is able to simultaneously generate neutrino masses and to account for a successful baryogenesis via leptogenesis. The sterile fermions involved in the leptogenesis process have masses at the GeV scale. We determine the viable parameter space that complies with both the neutrino and baryogenesis phenomenology, and analyse the different regimes for the generation of a lepton asymmetry in the early Universe (weak and strong-washout) in order to determine their testability in future experimental facilities.

Comments: 8 pages, 4 figures. To appear in the proceedings of the 51st Rencontres de Moriond EW 2016, 12-19 March 2016 in La Thuile, Italy. v2: discussion on thermal leptogenesis extended, references added