Halo-Independent Dark Matter Electron Scattering Analysis with In-Medium Effects

TL;DR

This paper enhances halo-independent dark matter-electron scattering analysis by incorporating in-medium effects via dielectric functions, crucial for accurate interpretation of germanium and silicon detector data in sub-GeV DM searches.

Contribution

It extends the halo-independent analysis method to include in-medium effects, improving the accuracy of local dark matter halo property inference.

Findings

In-medium effects significantly alter response functions for germanium and silicon.

Including dielectric functions is essential for correct analysis of direct DM detection data.

The method improves the robustness of sub-GeV dark matter searches.

Abstract

Dark matter (DM)-electron scattering is a prime target of a number of direct DM detection experiments and constitutes a promising avenue for exploring interactions of DM in the sub-GeV mass-range, challenging to probe with nuclear recoils. We extend the recently proposed halo-independent analysis method for DM-electron scattering, which allows to infer the local DM halo properties without any additional assumptions about them, to include in-medium effects through dielectric functions of the target material. We show that in-medium effects could significantly affect halo-independent analysis response functions for germanium and silicon and thus are essential for proper inference of local DM halo characteristics from direct DM detection data.