Halo-independent analysis of direct detection data for light WIMPs

TL;DR

This paper conducts a halo-independent analysis of direct detection data for light WIMPs, examining experimental results and tensions among different detectors under various interaction assumptions.

Contribution

It introduces a halo-independent framework to analyze light WIMP data, incorporating new experimental results and exploring interaction scenarios to assess data compatibility.

Findings

Low quenching factors challenge DAMA compatibility with halo models.

Tensions among CoGeNT, DAMA, and silicon data are identified.

Difficulty in unifying modulated and unmodulated signals as a single WIMP hypothesis.

Abstract

We present a halo-independent analysis of direct detection data on "light WIMPs," i.e. weakly interacting massive particles with mass close to or below 10 GeV/c^2. We include new results from silicon CDMS detectors (bounds and excess events), the latest CoGeNT acceptances, and recent measurements of low sodium quenching factors in NaI crystals. We focus on light WIMPs with spin-independent isospin-conserving and isospin-violating interactions with nucleons. For these dark matter candidates we find that a low quenching factor would make the DAMA modulation incompatible with a reasonable escape velocity for the dark matter halo, and that the tension among experimental data tightens in both the isospin-conserving and isospin-violating scenarios. We also find that a new although milder tension appears between the CoGeNT and DAMA annual modulations on one side and the silicon excess events on the other, in that it seems difficult to interpret them as the modulated and unmodulated aspects of the same WIMP dark matter signal.