Isospin-Violating Dark Matter

TL;DR

This paper explores isospin-violating dark matter, introducing a neutron-to-proton coupling ratio, which reconciles conflicting experimental signals and predicts future detectable signals, supported by a quark-level model.

Contribution

It introduces a parameter for isospin violation in dark matter interactions, unifies experimental results, and provides a consistent quark-level model for IVDM.

Findings

DAMA and CoGeNT signals can be compatible with XENON constraints under IVDM.

Predictions of near-future signals at XENON and CRESST.

A quark-level realization of IVDM consistent with collider bounds.

Abstract

Searches for dark matter scattering off nuclei are typically compared assuming that the dark matter's spin-independent couplings are identical for protons and neutrons. This assumption is neither innocuous nor well motivated. We consider isospin-violating dark matter (IVDM) with one extra parameter, the ratio of neutron to proton couplings, and include the isotope distribution for each detector. For a single choice of the coupling ratio, the DAMA and CoGeNT signals are consistent with each other and with current XENON constraints, and they unambiguously predict near future signals at XENON and CRESST. We provide a quark-level realization of IVDM as WIMPless dark matter that is consistent with all collider and low-energy bounds.