Low scale thermal leptogenesis in neutrinophilic Higgs doublet models

Understand

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.