Inelastic Dark Matter in Light of DAMA/LIBRA

TL;DR

This paper explores inelastic dark matter as an explanation for the DAMA annual modulation signal, showing how it can reconcile with null results from other experiments and making predictions for future tests.

Contribution

It demonstrates that inelastic dark matter models can explain DAMA's signal while remaining consistent with null results from other direct detection experiments.

Findings

Inelastic dark matter predicts signals mainly between 20-45 keV at xenon and iodine detectors.

Recent CRESST data with tungsten events are compatible with inelastic dark matter.

Future CRESST observations could confirm or exclude this dark matter scenario.

Abstract

Inelastic dark matter, in which WIMP-nucleus scatterings occur through a transition to an excited WIMP state ~ 100 keV above the ground state, provides a compelling explanation of the DAMA annual modulation signal. We demonstrate that the relative sensitivities of various dark matter direct detection experiments are modified such that the DAMA annual modulation signal can be reconciled with the absence of a reported signal at CDMS-Soudan, XENON10, ZEPLIN, CRESST, and KIMS for inelastic WIMPs with masses O(100 GeV). We review the status of these experiments, and make predictions for upcoming ones. In particular, we note that inelastic dark matter leads to highly suppressed signals at low energy, with most events typically occurring between 20 to 45 keV (unquenched) at xenon and iodine experiments, and generally no events at low (~ 10 keV) energies. Suppressing the background in this high energy region is essential to testing this scenario. The recent CRESST data suggest seven observed tungsten events, which is consistent with expectations from this model. If the tungsten signal persists at future CRESST runs, it would provide compelling evidence for inelastic dark matter, while its absence should exclude it.