Strong thermal leptogenesis and the N2-dominated scenario

Abstract

We briefly review the main aspects of leptogenesis, pointing out the main reasons that draw attention to the so-called N2-dominated scenario. We consider the conditions that stem out when the final asymmetry is required to be fully independent of the initial conditions. We show that in this scenario, called strong thermal leptogenesis, when barring special cancellations in the seesaw formula and in the flavoured decay parameters, a lightest neutrino mass m1 ≳ 10 meV for normal ordering and m1 ≳ 3 meV for inverted ordering are favoured. We then focus on the S O(10)-inspired leptogenesis models that naturally realise N2-dominated leptogenesis. We show how the combination with the strong thermal leptogenesis conditions yields important predictions on neutrino parameters. Finally, we briefly comment on the power of forthcoming neutrino experiments to either support or severely corner these leptogenesis scenarios.