Supersymmetric SO(10)-inspired leptogenesis and a new N₂-dominated scenario

Abstract

We study the supersymmetric extension of SO(10)-inspired thermal leptogenesis showing the constraints on neutrino parameters and on the reheat temperature TRH that derive from the condition of successful leptogenesis from next-to-lightest right handed (RH) neutrinos (N2) decays and the more stringent ones when independence of the initial conditions (strong thermal leptogenesis) is superimposed. In the latter case, the increase of the lightest right-handed neutrino (N1) decay parameters helps the wash-out of a pre-existing asymmetry and constraints relax compared to the non-supersymmetric case. We find significant changes especially in the case of large tan β values (gsim 15). In particular, for normal ordering, the atmospheric mixing angle can now be also maximal. The lightest left-handed neutrino mass is still constrained within the range 10 lesssim m1/meV lesssim 30 (corresponding to 75lesssim Σi mi/meV lesssim 120). Inverted ordering is still disfavoured, but an allowed region satisfying strong thermal leptogenesis opens up at large tan β values. We also study in detail the lower bound on TRH finding TRH gsim 1 × 1010 GeV independently of the initial N2 abundance. Finally, we propose a new N2-dominated scenario where the N1 mass is lower than the sphaleron freeze-out temperature. In this case there is no N1 wash-out and we find TRH gsim 1× 109 GeV . These results indicate that SO(10)-inspired thermal leptogenesis can be made compatible with the upper bound from the gravitino problem, an important result in light of the role often played by supersymmetry in the quest of a realistic model of fermion masses.

More information

Identifiers

Catalogue record

Export record

Altmetrics