Enhanced prospects for direct detection of inelastic dark matter from a non-galactic diffuse component

TL;DR

This paper explores how non-galactic diffuse dark matter components, bound to larger cosmic structures, can enhance the sensitivity of direct detection experiments for inelastic dark matter, expanding the potential for discovery.

Contribution

It quantifies the impact of non-galactic diffuse dark matter on direct detection sensitivity for inelastic scattering, a novel consideration in dark matter searches.

Findings

Enhanced detection sensitivity due to higher velocity dark matter components.

Implications for models with inelastic scattering mechanisms.

Potential to probe previously inaccessible parameter space.

Abstract

In some scenarios, the dark matter particle predominantly scatters inelastically with the target, producing a heavier neutral particle in the final state. In this class of scenarios, the reach in parameter space of direct detection experiments is limited by the velocity of the dark matter particle, usually taken as the escape velocity from the Milky Way. On the other hand, it has been argued that a fraction of the dark matter particles in the Solar System could be bound to the envelope of the Local Group or to the Virgo Supercluster, and not to our Galaxy, and therefore could carry velocities larger than the escape velocity from the Milky Way. In this paper we estimate the enhancement in sensitivity of current direct detection experiments to inelastic dark matter scatterings with nucleons or electrons due to the non-galactic diffuse components, and we discuss the implications for some well motivated models.