Strong Upper Limits on Sterile Neutrino Warm Dark Matter

TL;DR

This paper uses gamma-ray observations from INTEGRAL to set new, stringent limits on sterile neutrino dark matter properties, significantly narrowing the viable parameter space for these particles as warm dark matter candidates.

Contribution

It provides the most restrictive bounds to date on sterile neutrino mixing angles using gamma-ray line emission data from the Galactic Center.

Findings

Gamma-ray line emission limits constrain sterile neutrino models.

New bounds improve previous constraints by over two orders of magnitude.

Results significantly restrict sterile neutrino dark matter parameter space.

Abstract

Sterile neutrinos are attractive dark matter candidates. Their parameter space of mass and mixing angle has not yet been fully tested despite intensive efforts that exploit their gravitational clustering properties and radiative decays. We use the limits on gamma-ray line emission from the Galactic Center region obtained with the SPI spectrometer on the INTEGRAL satellite to set new constraints, which improve on the earlier bounds on mixing by more than two orders of magnitude, and thus strongly restrict a wide and interesting range of models.