Low scale thermal leptogenesis in neutrinophilic Higgs doublet models

TL;DR

This paper demonstrates that low-scale thermal leptogenesis is feasible in a neutrinophilic Higgs doublet model, which allows large Yukawa couplings and avoids washout effects, providing a viable explanation for matter-antimatter asymmetry.

Contribution

The study introduces a two Higgs doublet model with a tiny VEV for neutrino masses, enabling successful low-scale thermal leptogenesis without gravitino problems in supersymmetric scenarios.

Findings

Large Yukawa couplings produce sufficient CP asymmetry.

Leptogenesis occurs effectively at low energy scales.

Compatibility with neutralino dark matter and baryon asymmetry.

Abstract

It is well-known that leptogenesis in low energy scale is difficult in the conventional Type-I seesaw mechanism with hierarchical right-handed neutrino masses. We show that in a class of two Higgs doublet model, where one Higgs doublet generates masses of quarks and charged leptons whereas the other Higgs doublet with a tiny vacuum expectation value generates neutrino Dirac masses, large Yukawa couplings lead to a large enough CP asymmetry of the right-handed neutrino decay. Thermal leptogenesis suitably works at low energy scale as keeping no enhancement of lepton number violating wash out effects. We will also point out that thermal leptogenesis works well without confronting gravitino problem in a supersymmetric neutrinophilic Higgs doublet model with gravity mediated supersymmetry breaking. Neutralino dark matter and baryon asymmetry generation by thermal leptogenesis are easily compatible in our setup.