Discriminating Dark Matter Origins with Directional Detection

TL;DR

This paper explores how directional detection can differentiate between various origins of dark matter particles, especially boosted populations, using gas time-projection chambers to identify anisotropic signals.

Contribution

It introduces a method to distinguish dark matter origins based on directional recoil events, quantifying the number needed for reliable discrimination.

Findings

Standard halo dark matter can be distinguished from boosted populations with about 20 events.

Directional detection significantly enhances the ability to identify dark matter sources.

Relativistic dark matter fluxes from cosmic rays and supernovae produce detectable anisotropic signals.

Abstract

Scenarios where dark matter is boosted to relativistic velocities provide a promising probe of sub-GeV dark matter. Cosmic-ray upscattered and supernova-produced dark matter generate relativistic fluxes peaked toward the Galactic Centre, an anisotropy that offers a strong directional signature and is not mimicked by any terrestrial or cosmic background. We determine how many directional recoil events are required in a gas time-projection chamber to distinguish various scenarios for the origin of dark matter particles arriving in the solar system, which are otherwise indistinguishable without directionality. We find that standard halo dark matter particles can be distinguished from boosted populations with as few as $\mathcal{O}(20)$ events under reasonable track reconstruction performance and background conditions.