Discrimination of anisotropy in dark matter velocity distribution with directional detectors

TL;DR

This paper explores how directional detectors can distinguish between isotropic and anisotropic dark matter velocity distributions, demonstrating discrimination at 90% confidence with around 10,000 signals.

Contribution

It introduces a method to discriminate dark matter velocity anisotropy using directional detection data and simulations, highlighting the potential of such detectors for dark matter studies.

Findings

Anisotropy can be distinguished at 90% confidence level.

Discrimination is feasible with approximately 10,000 signals.

Two types of detector data were analyzed: angular histogram and energy-angular distribution.

Abstract

Directional detection of dark matter has sensitivity for both recoil energy and direction of nuclear recoil. It opens the way to measure local velocity distribution of dark matter. In this paper, we study possibility to discriminate isotropic distribution and anisotropic one suggested by a N-body simulation with directional detector. Numerical simulation is performed for two cases according to the detectors, one corresponds to angular histogram and the other is energy-angular distribution of the signals. We reveal that the anisotropy of velocity distribution can be discriminated at 90% C.L. with chi-squared test if O($10^4$) signals are obtained.