Directly detecting Isospin-Violating Dark Matter

TL;DR

This paper evaluates how future direct detection experiments can identify isospin-violating dark matter interactions, especially with xenon and neon detectors, to distinguish them from isospin-invariant models.

Contribution

It analyzes the potential of multiple experiments to detect isospin-violation in dark matter interactions, focusing on specific mediator models and optimal detector combinations.

Findings

Dark photon- and Z-mediated models are most distinguishable from isospin-invariant cases.

Large exposure xenon- and neon-based detectors improve detection prospects.

Approximately 100 ton-year exposure is needed to differentiate models just beyond current limits.

Abstract

We consider the prospects for multiple dark matter direct detection experiments to determine if the interactions of a dark matter candidate are isospin-violating. We focus on theoretically well-motivated examples of isospin-violating dark matter (IVDM), including models in which dark matter interactions with nuclei are mediated by a dark photon, a Z, or a squark. We determine that the best prospects for distinguishing IVDM from the isospin-invariant scenario arise in the cases of dark photon- or Z-mediated interactions, and that the ideal experimental scenario would consist of large exposure xenon- and neon-based detectors. If such models just evade current direct detection limits, then one could distinguish such models from the standard isospin-invariant case with two detectors with of order 100 ton-year exposure.