Low-scale leptogenesis with Dirac phase CP-violation

The freeze-in scenario of leptogenesis via oscillations within the type-I seesaw model with two quasi-degenerate heavy Majorana neutrinos N₁, ₂ can be viable in the mass range M (0. 1-100) \, GeV even when the Dirac phase of the Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing matrix is the only source of CP-violation in the leptonic sector and in leptogenesis. In particular, viable leptogenesis with Dirac phase CP-violation is compatible with N₁, \, ₂ total squared coupling to the Standard Model leptons within the reach of future planned and proposed experiments. Moreover, the parameter space differs from the one associated with the Casas-Ibarra sources of CP-violation. Future precise determination of and/or the N₁, ₂ couplings to the Standard Model leptons could establish whether, within the context of low-scale leptogenesis, the Dirac phase alone can be responsible for the present baryon asymmetry of the Universe.