The Astrophysical Uncertainties Of Dark Matter Direct Detection Experiments

TL;DR

This paper examines how astrophysical uncertainties, like galactic velocities and velocity distributions, impact dark matter direct detection limits across different scattering scenarios, highlighting significant effects for light dark matter and robustness for heavier masses.

Contribution

It provides a comprehensive analysis of astrophysical uncertainties on detection limits, including the use of simulated velocity distributions, which was not extensively explored before.

Findings

Varying galactic escape velocity affects limits for light dark matter.

Maxwell-Boltzmann distribution often yields less constraining limits than simulated distributions.

Limits for dark matter masses above 50 GeV are robust against astrophysical uncertainties.

Abstract

The effects of astrophysical uncertainties on the exclusion limits at dark matter direct detection experiments are investigated for three scenarios: elastic, momentum dependent and inelastically scattering dark matter. We find that varying the dark matter galactic escape velocity and the Sun's circular velocity can lead to significant variations in the exclusion limits for light ($\lesssim10$ GeV) elastic and inelastic scattering dark matter. We also calculate the limits using one hundred velocity distributions extracted from the Via Lactea II and GHALO N-body simulations and find that a Maxwell-Boltzmann distribution with the same astrophysical parameters generally sets less constraining limits. The elastic and momentum dependent limits remain robust for masses $\gtrsim50$ GeV under variations of the astrophysical parameters and the form of the velocity distribution.