Improvement of the Determination of the WIMP Mass from Direct Dark Matter Detection Data

TL;DR

This paper presents an improved, model-independent method for determining WIMP mass from direct detection data, reducing systematic deviations and statistical errors, enabling more accurate mass estimation with limited events.

Contribution

The authors developed an enhanced method that minimizes systematic deviations and statistical errors in WIMP mass determination, independent of WIMP density and velocity distribution.

Findings

Systematic deviation for heavy WIMPs was reduced.

WIMP mass of ~50 GeV can be estimated with ~35% error.

Method works with as few as 100 events from two detectors.

Abstract

Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. We developed a model-independent method for determining the WIMP mass by using data (i.e., measured recoil energies) of direct detection experiments. Our method is independent of the as yet unknown WIMP density near the Earth, of the form of the WIMP velocity distribution, as well as of the WIMP-nucleus cross section. It requires however positive signals from at least two detectors with different target nuclei. At the first phase of this work we found a systematic deviation of the reconstructed WIMP mass from the real one for heavy WIMPs. Now we improved this method so that this deviation can be strongly reduced for even very high WIMP mass. The statistical error of the reconstructed mass has also been reduced. In a background-free evironment, a WIMP mass of ~ 50 GeV could in principle be determined with an error of ~ 35% with only 2 times 50 events.