Direct constraints on charged excitations of dark matter

TL;DR

This paper demonstrates how neutrinoless double-beta decay experiments can directly constrain the formation of bound states between weak-scale dark matter particles and nuclei, providing new limits on certain dark matter models.

Contribution

It introduces a novel method to constrain charged excitations of dark matter using double-beta decay experiments, complementing existing cosmological and collider constraints.

Findings

Double-beta decay experiments set new bounds on WIMP-nucleus bound state formation.

Charged excitations with mass gaps less than ~20 MeV are constrained.

The method is sensitive to a large parameter space of the WIMP doublet model.

Abstract

If the neutral component of weak-scale dark matter is accompanied by a charged excitation separated by a mass gap of less than ~20 MeV, WIMPs can form stable bound states with nuclei. We show that the recent progress in experiments searching for neutrinoless double-beta decay sets the first direct constraint on the exoergic reaction of WIMP-nucleus bound state formation. We calculate the rate for such process in representative models and show that the double-beta decay experiments provide unique sensitivity to a large fraction of parameter space of the WIMP doublet model, complementary to constraints imposed by cosmology and direct collider searches.