Constraints on low-mass WIMPs from the EDELWEISS-III dark matter search

摘要

We present the results of a search for elastic scattering from galactic dark matterudin the form of Weakly Interacting Massive Particles (WIMPs) in the 4 − 30 GeV/c2 massudrange. We make use of a 582 kg-day fiducial exposure from an array of 800 g Germaniumudbolometers equipped with a set of interleaved electrodes with full surface coverage. Weudsearched specifically for ∼ 2.5 − 20 keV nuclear recoils inside the detector fiducial volume.udAs an illustration the number of observed events in the search for 5 (resp. 20) GeV/c2udWIMPs are 9 (resp. 4), compared to an expected background of 6.1 (resp. 1.4). A 90% CLudlimit of 4.3 × 10−40 cm2ud(resp. 9.4 × 10−44 cm2ud) is set on the spin-independent WIMPnucleonudscattering cross-section for 5 (resp. 20) GeV/c2 WIMPs. This result represents aud41-fold improvement with respect to the previous EDELWEISS-II low-mass WIMP search forud7 GeV/c2 WIMPs. The derived constraint is in tension with hints of WIMP signals from someudrecent experiments, thus confirming results obtained with different detection techniques.