Imprint of the seesaw mechanism on feebly interacting dark matter and the baryon asymmetry

TL;DR

This paper explores how the type-I seesaw mechanism can naturally produce a feebly interacting dark matter candidate and explains the baryon asymmetry, linking neutrino masses, dark matter properties, and leptogenesis.

Contribution

It demonstrates that the seesaw mechanism can generate a freeze-in dark matter particle with a small active neutrino mass and connects leptogenesis to neutrino data and Higgs stability.

Findings

Dark matter mass $oxed{ ext{less than 1 MeV}}$ from non-thermal production.

Smallest active neutrino mass $oxed{ ext{around } 10^{-12} ext{ eV}}$.

Leptogenesis scale fixed by neutrino data and Higgs stability.

Abstract

We show that the type-I seesaw, responsible for generating the light neutrino mass, itself is capable of accommodating one of the three right handed neutrinos as a freeze-in type of dark matter (DM) where the required smallness of the associated coupling is connected to the lightness of the (smallest) active neutrino mass. It turns out that (a) the non-thermal production of DM having mass $\lesssim \mathcal{O}(1)$ MeV (via decays of $W, Z$ bosons and SM Higgs) consistent with relic density as well as (b) its stability determine this smallest active neutrino mass uniquely $\sim {\mathcal{O}}(10^{-12})$ eV. On the other hand, the study of flavor leptogenesis in this scenario (taking into account the latest neutrino data and Higgs vacuum stability issue) fixes the scale of two other right handed neutrinos.