Solar Reflection of Dark Matter

TL;DR

This paper investigates how light dark matter particles scattering off solar electrons create a detectable flux, updating previous models with simulations to improve detection prospects in underground experiments.

Contribution

It extends prior work by analyzing dark matter scattering via light mediators in the Sun and providing updated energy spectra and detection rate predictions.

Findings

XENON1T provides the strongest limits for sub-MeV dark matter.

Sensitivity to dark matter charge can reach below 10^{-9}e.

Reflected dark matter flux offers a new detection channel.

Abstract

The scattering of light dark matter off thermal electrons inside the Sun produces a "fast" sub-component of the dark matter flux that may be detectable in underground experiments. We update and extend previous work by analyzing the signatures of dark matter candidates which scatter via light mediators. Using numerical simulations of the dark matter-electron interaction in the solar interior, we determine the energy spectrum of the reflected flux, and calculate the expected rates for direct detection experiments. We find that large Xenon-based experiments (such as XENON1T) provide the strongest direct limits for dark matter masses below a few MeV, reaching a sensitivity to the effective dark matter charge of better than $\sim 10^{-9}e$.