Testing keV sterile neutrino dark matter in future direct detection experiments

TL;DR

This paper explores how future direct detection experiments can set laboratory bounds on keV-scale sterile neutrino dark matter by analyzing electron recoil signals, providing the first direct constraints of this kind.

Contribution

It introduces a method to constrain sterile neutrino dark matter using direct detection experiments, complementing astrophysical bounds.

Findings

XENON100, XENON1T, and DARWIN can detect inelastic scattering signals.

Laboratory bounds are weaker than astrophysical X-ray constraints but are the first direct limits.

Some parameter space regions will have the strongest laboratory constraints on keV neutrinos.

Abstract

We determine constraints on sterile neutrino warm dark matter through direct detection experiments, taking XENON100, XENON1T and DARWIN as examples. If keV-scale sterile neutrinos scatter inelastically with bound electrons of the target material, an electron recoil signal is generated. This can be used to set limits on the sterile neutrino mass and its mixing with the active sector. While not competitive with astrophysical constraints from X-ray data, the constraints are the first direct laboratory bounds on sterile neutrino warm dark matter, and will be in some parts of parameter space the strongest limits on keV-scale neutrinos.