WIMP-Search Results from the Second CDMSlite Run

TL;DR

This paper reports on the second CDMSlite run using cryogenic germanium detectors with a low energy threshold, setting new limits on WIMP-nucleon interactions for low-mass WIMPs in the 1.6 to 5.5 GeV/c^2 range.

Contribution

It introduces improved detection sensitivity and background reduction techniques, extending the exclusion limits for low-mass WIMPs in direct detection experiments.

Findings

Excluded new parameter space for WIMP masses 1.6-5.5 GeV/c^2

Achieved an energy threshold as low as 56 eV for electron recoils

Reduced backgrounds compared to previous CDMSlite results

Abstract

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg days, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/$c^2$.