Successful type I Leptogenesis with SO(10)-inspired mass relations

TL;DR

This paper demonstrates that successful type I leptogenesis within SO(10)-inspired models is achievable by considering next-to-lightest neutrino decays and flavor effects, overcoming previous theoretical obstacles.

Contribution

It shows how to realize successful leptogenesis under SO(10) constraints by including flavor effects and decays of heavier right-handed neutrinos, with specific conditions on neutrino parameters.

Findings

Successful leptogenesis requires m_1  0.001 eV.

Non-zero _13 favors normal hierarchical neutrino spectrum.

Flavor effects and next-to-lightest neutrino decays are crucial for viability.

Abstract

It is well-known that thermal leptogenesis through the decays of the lightest right-handed neutrinos encounters serious difficulties when SO(10)-inspired mass conditions are imposed on the Dirac neutrino mass matrix and light neutrino masses are generated through the type I see-saw mechanism. We show that these can be circumvented when the production from the next-to-lightest right-handed neutrinos and flavor effects are properly taken into account. Some conditions on the low energy parameters have to be satisfied in order for inverse processes involving the lightest right-handed neutrino not to wash-out the asymmetry. In particular we find m_1 \gtrsim 0.001 eV, where m_1 is the mass of the lightest left-handed neutrino and that non-vanishing values of the mixing angle theta_13 are preferred in the case of a normal fully hierarchical spectrum of light neutrinos.