Combined Limits on WIMPs from the CDMS and EDELWEISS Experiments

TL;DR

This paper combines results from the CDMS and EDELWEISS dark matter experiments to set improved limits on WIMP-nucleon interactions, enhancing sensitivity across a range of WIMP masses.

Contribution

It presents a combined analysis of two leading cryogenic germanium detector experiments, improving constraints on WIMP cross-sections and demonstrating a straightforward combination method.

Findings

Excluded WIMP-nucleon cross-section of 3.3 x 10^{-44} cm^2 at 90% CL for 90 GeV/c^2 WIMPs.

Combination improves individual limits by a factor of 1.6 above 700 GeV/c^2.

Alternative combination methods yield stronger or weaker constraints depending on WIMP mass range.

Abstract

The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors. The total data set represents 614 kg.d equivalent exposure. A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments. The results are interpreted in terms of limits on spin-independent WIMP-nucleon cross-section. For a WIMP mass of 90 GeV/c^2, where this analysis is most sensitive, a cross-section of 3.3 x 10^{-44} cm^2 is excluded at 90% CL. At higher WIMP masses, the combination improves the individual limits, by a factor 1.6 above 700 GeV/c^2. Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others.