Global interpretation of direct Dark Matter searches after CDMS-II results

TL;DR

This paper conducts a comprehensive analysis of dark matter direct detection data, including recent CDMS-II results, to interpret signals like DAMA and assess the viability of various interaction models, highlighting spin-dependent inelastic scattering off protons as a promising scenario.

Contribution

It provides the first global fit combining CDMS-II, DAMA, and CoGeNT data, evaluating multiple dark matter interaction models and identifying spin-dependent inelastic scattering off protons as a consistent explanation.

Findings

Spin-dependent inelastic scattering off protons fits all data well.

Most other models are disfavored or require fine tuning.

CDMS-II events could be interpreted as elastic dark matter scattering.

Abstract

We perform a global fit to data from Dark Matter (DM) direct detection experiments, including the recent CDMS-II results. We discuss possible interpretations of the DAMA annual modulation signal in terms of spin-independent and spin-dependent DM-nucleus interactions, both for elastic and inelastic scattering. We find that in the spin-dependent inelastic scattering off protons a good fit to all data is obtained. We present a simple toy model realizing such a scenario. In all the remaining cases the DAMA allowed regions are disfavored by other experiments or suffer from severe fine tuning of DM parameters with respect to the galactic escape velocity. Finally, we also entertain the possibility that the two events observed in CDMS-II are an actual signal of elastic DM scattering, and we compare the resulting CDMS-II allowed regions to the exclusion limits from other experiments. In this arXiv version of the manuscript we also provide in appendix A the updated fits including recent CoGeNT results.