(Almost) Closing the $\nu$MSM Sterile Neutrino Dark Matter Window with NuSTAR

TL;DR

This paper uses NuSTAR X-ray observations of the Galactic Center to set the strongest limits to date on sterile neutrino dark matter in the 10-50 keV mass range, significantly constraining the parameter space.

Contribution

It provides the most stringent observational limits on sterile neutrino dark matter in the 10-50 keV range using NuSTAR data, reducing the viable parameter space.

Findings

No evidence of unknown X-ray lines from sterile neutrino decay.

Limits on sterile neutrino mass and mixing angle are the strongest to date.

Allowed parameter space in the minimal standard model is significantly reduced.

Abstract

We use NuSTAR observations of the Galactic Center to search for X-ray lines from the radiative decay of sterile neutrino dark matter. Finding no evidence of unknown lines, we set limits on the sterile neutrino mass and mixing angle. In most of the mass range 10-50 keV, these are now the strongest limits, at some masses improving upon previous limits by a factor of ~10. In the neutrino minimal standard model framework, where additional constraints from dark matter production and structure formation apply, the allowed parameter space is reduced by more than half. Future NuSTAR observations may be able to cover much of the remaining parameter space.