Constraints on low-mass, relic dark matter candidates from a surface-operated SuperCDMS single-charge sensitive detector

TL;DR

This paper reports new experimental limits on low-mass dark matter interactions, using a highly sensitive surface-operated SuperCDMS detector with eV-scale resolution, constraining various dark matter models in the sub-keV to MeV mass range.

Contribution

It introduces a second-generation SuperCDMS detector with high energy resolution and reports the first constraints on light dark matter-electron interactions, dark photon, and axion-like particles from surface operation.

Findings

Set upper limits on dark matter-electron cross section at 8.7×10⁻³⁴ cm²

Constrained dark photon kinetic mixing parameter to 3.3×10⁻¹⁴

Limited axioelectric coupling constant to 1.0×10⁻⁹

Abstract

This article presents an analysis and the resulting limits on light dark matter inelastically scattering off of electrons, and on dark photon and axion-like particle absorption, using a second-generation SuperCDMS high-voltage eV-resolution detector. The 0.93 gram Si detector achieved a 3 eV phonon energy resolution; for a detector bias of 100 V, this corresponds to a charge resolution of 3% of a single electron-hole pair. The energy spectrum is reported from a blind analysis with 1.2 gram-days of exposure acquired in an above-ground laboratory. With charge carrier trapping and impact ionization effects incorporated into the dark matter signal models, the dark matter-electron cross section $\bar{\sigma}_{e}$ is constrained for dark matter masses from 0.5--$10^{4} $MeV$/c^{2}$; in the mass range from 1.2--50 eV$/c^{2}$ the dark photon kinetic mixing parameter $\varepsilon$ and the axioelectric coupling constant $g_{ae}$ are constrained. The minimum 90% confidence-level upper limits within the above mentioned mass ranges are $\bar{\sigma}_{e}\,=\,8.7\times10^{-34}$ cm$^{2}$, $\varepsilon\,=\,3.3\times10^{-14}$, and $g_{ae}\,=\,1.0\times10^{-9}$.