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 which generates neutrino masses. Thanks to this tiny vacuum expectation value of the neutrinophilic Higgs, our model allows us to reduce the mass of the lightest right-handed (s)neutrino to be $\mathcal{O}({10}^5)\mathrm{GeV}$, keeping sufficiently large $CP$ asymmetry in its decay. Therefore, the reheating temperature after inflation is not necessarily high; hence this scenario is free from the gravitino problem.

• Received 27 June 2011

DOI:https://doi.org/10.1103/PhysRevD.84.103524