Probing Freeze-in Dark Matter via Heavy Neutrino Portal

TL;DR

This paper investigates how freeze-in dark matter produced through a right-handed neutrino portal can be detected using current and future experiments searching for heavy neutrinos, focusing on a minimal type-I seesaw model.

Contribution

It demonstrates that sub-TeV scale freeze-in dark matter models are testable with existing and upcoming collider and beam dump experiments within a simplified four-parameter framework.

Findings

Allowed parameter space is within reach of current experiments.

Feebly-coupled heavy neutrinos can be probed via collider searches.

Freeze-in dark matter can be tested in the sub-TeV mass range.

Abstract

We explore the possibility of probing freeze-in dark matter (DM) produced via the right-handed neutrino (RHN) portal using the RHN search experiments. We focus on a simplified framework of minimally-extended type-I seesaw model consisting of only four free parameters, namely the RHN mass, the fermionic DM mass, the Yukawa coupling between the DM and the RHN, and a real singlet scalar mass. We consider two cases for the DM production either via decay of the thermal RHN or via scattering of the bath particles mediated by the RHN. In both cases, we show that for sub-TeV scale DM masses, the allowed model parameter space satisfying the observed DM relic density for freeze-in scenario falls within the reach of current and future collider, beam dump and forward physics facilities looking for feebly-coupled heavy neutrinos.