Two radiative inverse seesaw models, dark matter, and baryogenesis

TL;DR

This paper explores two radiative inverse seesaw models' implications for neutrino masses, baryogenesis, and dark matter, analyzing their cosmological viability and detection prospects.

Contribution

It compares two contrasting radiative inverse seesaw models, analyzing their effects on baryogenesis and dark matter, highlighting differences in their cosmological and detection implications.

Findings

Ma model can generate baryon asymmetry via resonant leptogenesis.

Law/McDonald model supports a Higgs-portal dark matter scenario.

Ma model's dark matter candidate tends to overclose the universe.

Abstract

The inverse seesaw mechanism allows the neutrino masses to be generated by new physics at an experimentally accessible scale, even with O(1) Yukawa couplings. In the inverse seesaw scenario, the smallness of neutrino masses is linked to the smallness of a lepton number violating parameter. This parameter may arise radiatively. In this paper, we study the cosmological implications of two contrasting radiative inverse seesaw models, one due to Ma and the other to Law and McDonald. The former features spontaneous, the latter explicit lepton number violation. First, we examine the effect of the lepton-number violating interactions introduced in these models on the baryon asymmetry of the universe. We investigate under what conditions a pre-existing baryon asymmetry does not get washed out. While both models allow a baryon asymmetry to survive only once the temperature has dropped below the mass of their heaviest fields, the Ma model can create the baryon asymmetry through resonant leptogenesis. Then we investigate the viability of the dark matter candidates arising within these models, and explore the prospects for direct detection. We find that the Law/McDonald model allows a simple dark matter scenario similar to the Higgs portal, while in the Ma model the simplest cold dark matter scenario would tend to overclose the universe.