A CoGeNT Modulation Analysis

TL;DR

This paper analyzes CoGeNT data for modulation signals, finding inconsistencies with standard WIMP models and exploring alternative dark matter scenarios and halo models, with implications for other experiments.

Contribution

It introduces halo-independent analysis techniques to interpret modulation data and evaluates non-standard dark matter models against experimental results.

Findings

Modulation detected at high energies in CoGeNT data.

Standard elastic WIMP models do not fit the modulation well.

Inelastic dark matter models fit the modulation but not the spectrum.

Abstract

We analyze the recently released CoGeNT data with a focus on their time-dependent properties. Using various statistical techniques, we confirm the presence of modulation in the data, and find a significant component at high (E_{ee} > 1.5$ keVee) energies. We find that standard elastic WIMPs in a Maxwellian halo do not provide a good description of the modulation. We consider the possibility of non-standard halos, using halo independent techniques, and find a good agreement with the DAMA modulation for Q_{Na} \approx 0.3, but disfavoring interpretations with Q_{Na} = 0.5. The same techniques indicate that CDMS-Ge should see an O(1) modulation, and XENON100 should have seen 10-30 events (based upon the modulation in the 1.5-3.1 keVee range), unless L_{eff} is smaller than recent measurements. Models such as inelastic dark matter provide a good fit to the modulation, but not the spectrum. We note that tensions with XENON could be alleviated in such models if the peak is dominantly in April, when XENON data are not available due to noise.