Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB

TL;DR

This study reports on a low-mass WIMP search using the DAMIC detector at SNOLAB, setting new constraints on WIMP interactions and excluding certain parameter regions relevant to previous signals, demonstrating the potential of future larger detectors.

Contribution

First constraints on low-mass WIMPs using DAMIC silicon detectors with a 0.6 kg day exposure, excluding parameter space relevant to prior signals and showcasing future detector potential.

Findings

Constraints on spin-independent WIMP-nucleon cross section.

Exclusion of parameter space relevant to CDMS-II Si signals.

Demonstration of DAMIC's potential for low-mass WIMP detection.

Abstract

We present results of a dark matter search performed with a 0.6 kg day exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the bulk silicon of charge-coupled devices down to a signal of 60 eV electron equivalent. The data are consistent with radiogenic backgrounds, and constraints on the spin-independent WIMP-nucleon elastic-scattering cross section are accordingly placed. A region of parameter space relevant to the potential signal from the CDMS-II Si experiment is excluded using the same target for the first time. This result obtained with a limited exposure demonstrates the potential to explore the low-mass WIMP region (<10 GeV/$c^{2}$) of the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.