Search for annual modulation in low-energy CDMS-II data

TL;DR

This study searched for annual modulation signals in low-energy events from the CDMS-II dark matter experiment, finding no evidence of such modulation and constraining possible WIMP interactions, thereby challenging some previous claims of dark matter detection.

Contribution

The paper provides the first stringent limits on annual modulation of low-energy events in CDMS-II data, specifically constraining WIMP-induced signals in the 5-11.9 keVnr range.

Findings

No significant annual modulation detected in nuclear recoil events.

Limits on modulation amplitude are below 0.06 events/(keVnr·kg·day) at 99% CL.

Results disfavor WIMP explanations for CoGeNT modulation at >98% confidence.

Abstract

We report limits on annual modulation of the low-energy event rate from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Such a modulation could be produced by interactions from Weakly Interacting Massive Particles (WIMPs) with masses ~10 GeV/c^2. We find no evidence for annual modulation in the event rate of veto-anticoincident single-detector interactions consistent with nuclear recoils, and constrain the magnitude of any modulation to <0.06 event [keVnr kg day]^-1 in the 5-11.9 keVnr energy range at the 99% confidence level. These results disfavor an explanation for the reported modulation in the 1.2-3.2 keVee energy range in CoGeNT in terms of nuclear recoils resulting from elastic scattering of WIMPs at >98% confidence. For events consistent with electron recoils, no significant modulation is observed for either single- or multiple-detector interactions in the 3.0-7.4 keVee range.