Thermal leptogenesis in a supersymmetric neutrinophilic Higgs model

TL;DR

This paper explores a supersymmetric neutrinophilic Higgs model where a tiny Higgs VEV enables low-mass right-handed neutrinos, allowing successful thermal leptogenesis at lower reheating temperatures, avoiding gravitino issues.

Contribution

It introduces a neutrinophilic Higgs with a tiny VEV in a supersymmetric framework, enabling low-scale leptogenesis with reduced right-handed neutrino masses.

Findings

Allows right-handed neutrino masses around 10^5 GeV

Enables leptogenesis at lower reheating temperatures

Avoids gravitino overproduction problems

Abstract

We investigate thermal leptogenesis in a supersymmetric neutrinophilic Higgs model by taking phenomenological constraints into account, where, in addition to the minimal supersymmetric standard model, we introduce an extra Higgs field with a tiny vacuum expectation value (VEV) which generates neutrino masses. Thanks to this tiny VEV of the neutrinophilic Higgs, our model allows to reduce the mass of the lightest right-handed (s)neutrino to be ${\cal O}(10^5)$ GeV as keeping sufficiently large CP asymmetry in its decay. Therefore, the reheating temperature after inflation is not necessarily high, hence this scenario is free from gravitino problem.