Probing dark matter streams with CoGeNT

TL;DR

This paper investigates how dark matter streams, like the Sagittarius stream, can influence CoGeNT's detection sensitivity and interpretation of dark matter particle properties, emphasizing the importance of considering streams in data analysis.

Contribution

It demonstrates that dark matter streams can significantly affect CoGeNT results and provides a method to account for streams in interpreting experimental data.

Findings

Streams can cause CoGeNT to exclude or favor different halo models.

A 10 kg-year exposure can detect or exclude streams contributing as little as 3-5% of local dark matter.

Ignoring streams may lead to incorrect estimates of dark matter particle mass and cross section.

Abstract

We examine the future sensitivity of CoGeNT to the presence of dark matter streams and find that consideration of streams in the data may lead to differences in the interpretation of the results. We show the allowed particle mass and cross section for different halo parameters, assuming spin-independent elastic scattering. As an example, we choose a stream with the same velocity profile as that of the Sagittarius stream (and in the Solar neighborhood) and find that, with an exposure of $\sim$ 10 kg year, the CoGeNT results can be expected to exclude the SHM-only halo in favor of an SHM+stream halo at the 95% (99.7%) confidence level provided the stream contributes 3% (5%) of the local dark matter density. The presence of a significant stream component may result in incorrect estimates of the particle mass and cross section unless the presence of the stream is taken into account. We conclude that the CoGeNT experiment is sensitive to streams and care should be taken to include the possibility of streams when analyzing experimental results.