An Improved Bound on Accelerated Light Dark Matter

TL;DR

This paper investigates inelastic scattering effects in accelerated light dark matter interactions with Earth, revealing significant impacts on detection limits depending on mediator mass and kinetic energy spectrum.

Contribution

It provides the first detailed calculation of inelastic effects in dark matter--Earth scattering mediated by a vector particle, highlighting their importance for detection constraints.

Findings

Inelastic scattering effects can alter exclusion limits by tens of times for heavy mediators.

The impact depends strongly on mediator mass and dark matter kinetic energy spectrum.

Inelastic effects are crucial for accurate interpretation of dark matter detection experiments.

Abstract

Light (sub-GeV) dark matter has gained increasing interest in terms of direct detection. Accelerated dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub-GeV range. Because of the large kinetic energy, its interactions with the nucleus are predominantly governed by inelastic scattering, including quasi-elastic and deep inelastic scattering. In this work, we calculated the inelastic effects in dark matter--Earth scattering mediated by a vector particle. Our analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark matter. The results exhibited considerable disparity: the upper bounds of the exclusion limit for the spin-independent cross-section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered.