Leptogenesis Scenarios via Non-Thermally Produced Right-handed Neutrino and Sneutrino in Supersymmetric Seesaw Model

TL;DR

This paper explores leptogenesis via non-thermally produced right-handed (s)neutrinos from inflaton decay, analyzing various decay timings and their implications for baryon asymmetry and gravitino constraints in supersymmetric models.

Contribution

It introduces a comprehensive analysis of leptogenesis scenarios involving right-handed (s)neutrinos decaying after dominating the universe, including the novel case of relativistic neutrino decay.

Findings

Leptogenesis can occur if neutrinos decay after dominating the universe.

Relativistic neutrino decay can relax gravitino constraints.

Parameter dependence of leptogenesis scenarios is thoroughly analyzed.

Abstract

We reconsidered leptogenesis scenario from right-handed (s)neutrino produced by the decay of inflaton. Besides the well-investigated case that the neutrino decays instantaneously after the production, leptogenesis is possible if neutrino decays after it dominates the universe. In the latter case, right-handed (s)neutrino can decay either while it is relativistic or after it becomes non-relativistic. Especially, the first case has not been discussed seriously in literatures. Resultant lepton asymmetry and constraints from the gravitino problem are studied in broad parameter region, including all cases of this scenario. It is also shown how this leptogenesis scenario depends on the parameters, the inflaton decay rate (the reheating temperature), the right-handed neutrino mass, the washout parameter, and the constraint from the gravitino problem. Leptogenesis from relativistic neutrino decay is interesting because both thermal and non-thermal gravitino problems can be relaxed.