Constraints on dark photons and axion-like particles from SuperCDMS Soudan

TL;DR

This paper uses cryogenic germanium detectors from the SuperCDMS Soudan experiment to set new constraints on dark photons and axion-like particles in the sub-keV mass range, improving limits on their couplings assuming they make up all dark matter.

Contribution

It provides the first constraints on dark photon kinetic mixing and axion-like particle couplings below 1 keV/$c^2$ using cryogenic detector data.

Findings

Dark photon kinetic mixing parameter constrained below 10^{-15} around 100 eV/$c^2$

Axion-like particle axioelectric coupling constrained below 10^{-12} in the few-hundred eV/$c^2$ mass range

Excluded previously untested parameter space for masses below ~1 keV/$c^2$

Abstract

We present an analysis of electron recoils in cryogenic germanium detectors operated during the SuperCDMS Soudan experiment. The data are used to set new constraints on the axioelectric coupling of axion-like particles and the kinetic mixing parameter of dark photons, assuming the respective species constitutes all of the galactic dark matter. This study covers the mass range from 40 eV/$c^2$ to 500 eV/$c^2$ for both candidates, excluding previously untested parameter space for masses below ~1 keV/$c^2$. For the kinetic mixing of dark photons, values below $10^{-15}$ are reached for particle masses around 100 eV/$c^2$; for the axioelectric coupling of axion-like particles, values below $10^{-12}$ are reached for particles with masses in the range of a few-hundred eV/$c^2$.