Next decade of sterile neutrino studies

TL;DR

This paper reviews the current understanding of sterile neutrino dark matter, emphasizing the importance of astrophysical signals and proposing a dedicated X-ray spectrometer mission for future detection efforts.

Contribution

It highlights the potential of indirect astrophysical detection and suggests a dedicated X-ray mission as a novel approach to identify sterile neutrino dark matter.

Findings

Astrophysical signals may be the only way to detect sterile neutrino dark matter.

Synergy with accelerator experiments can help confirm the dark matter origin.

A dedicated X-ray spectrometer is proposed for future exploration.

Abstract

We review the status of sterile neutrino dark matter and discuss astrophysical and cosmological bounds on its properties as well as future prospects for its experimental searches. We argue that if sterile neutrinos are the dominant fraction of dark matter, detecting an astrophysical signal from their decay (the so-called 'indirect detection') may be the only way to identify these particles experimentally. However, it may be possible to check the dark matter origin of the observed signal unambiguously using its characteristic properties and/or using synergy with accelerator experiments, searching for other sterile neutrinos, responsible for neutrino flavor oscillations. We argue that to fully explore this possibility a dedicated cosmic mission - an X-ray spectrometer - is needed.