Hunting Sterile Neutrino Dark Matter in the MeV Gap

TL;DR

This paper assesses how upcoming MeV gamma-ray telescopes could significantly improve constraints on sterile neutrino dark matter in the 0.2-100 MeV mass range by analyzing their decay signals.

Contribution

It provides a Fisher forecast analysis demonstrating the potential of future MeV telescopes to detect or constrain sterile neutrino dark matter.

Findings

Future instruments can improve existing limits by several orders of magnitude.

Sterile neutrinos can produce observable photon signals through decay channels.

Next-generation telescopes have strong discovery potential in this mass range.

Abstract

We investigate the sensitivities of upcoming MeV gamma-ray telescopes to sterile neutrino dark matter in the mass range $(0.2-100)\,{\rm MeV}$. Sterile neutrinos in this regime can produce observable photon signals through radiative two-body decays and three-body decays with final-state radiation. We perform a Fisher forecasting analysis incorporating realistic astrophysical background modeling and detector response to derive projected constraints on the sterile neutrino decay rate. We find that future MeV instruments can improve existing limits by several orders of magnitude across a wide region of parameter space. Our results highlight the discovery potential of next-generation MeV telescopes in probing sterile neutrino dark matter.