The Scientific Reach of Multi-Ton Scale Dark Matter Direct Detection Experiments

TL;DR

Next-generation multi-ton scale dark matter detectors, like DARWIN, can provide detailed insights into dark matter properties, but face degeneracies influenced by mass, interaction types, and astrophysical uncertainties, especially for masses below 200 GeV.

Contribution

This study develops a detailed numerical model of the DARWIN detector, analyzing how multiple targets can help resolve dark matter parameter degeneracies and uncertainties.

Findings

Multi-ton detectors can distinguish dark matter properties for masses below 200 GeV.

Using two targets offers limited improvement over a single larger target in parameter determination.

Degeneracies depend on dark matter mass, isospin violation, and inelastic interactions.

Abstract

The next generation of large scale WIMP direct detection experiments have the potential to go beyond the discovery phase and reveal detailed information about both the particle physics and astrophysics of dark matter. We report here on early results arising from the development of a detailed numerical code modeling the proposed DARWIN detector, involving both liquid argon and xenon targets. We incorporate realistic detector physics, particle physics and astrophysical uncertainties and demonstrate to what extent two targets with similar sensitivities can remove various degeneracies and allow a determination of dark matter cross sections and masses while also probing rough aspects of the dark matter phase space distribution. We find that, even assuming dominance of spin-independent scattering, multi-ton scale experiments still have degeneracies that depend sensitively on the dark matter mass, and on the possibility of isospin violation and inelasticity in interactions. We find that these experiments are best able to discriminate dark matter properties for dark matter masses less than around 200 GeV. In addition, and somewhat surprisingly, the use of two targets gives only a small improvement (aside from the advantage of different systematics associated with any claimed signal) in the ability to pin down dark matter parameters when compared with one target of larger exposure.