On the DAMA and CoGeNT Modulations

TL;DR

This paper examines the annual modulation signals observed by DAMA and CoGeNT in dark matter detection, exploring how isospin-violating inelastic dark matter models can reconcile these signals with existing experimental constraints.

Contribution

It introduces isospin-violating inelastic dark matter as a mechanism to alleviate tensions between direct detection experiments' results.

Findings

Isospin-violation weakens XENON constraints.

Inelasticity increases modulation fraction, improving experiment agreement.

Models can marginally reconcile DAMA, CoGeNT, and CDMS results.

Abstract

DAMA observes an annual modulation in their event rate, as might be expected from dark matter scatterings, while CoGeNT has reported evidence for a similar modulation. The simplest interpretation of these findings in terms of dark matter-nucleus scatterings is excluded by other direct detection experiments. We consider the robustness of these exclusions with respect to assumptions regarding the scattering and find that isospin-violating inelastic dark matter helps alleviate this tension and allows marginal compatibility between experiments. Isospin-violation can significantly weaken the XENON constraints, while inelasticity enhances the annual modulation fraction of the signal, bringing the CoGeNT and CDMS results into better agreement.