First Germanium-Based Constraints on Sub-MeV Dark Matter with the EDELWEISS Experiment

Area of Science:

• Particle Physics
• Astrophysics
• Cosmology

Background:

• Dark matter (DM) remains a significant mystery in physics, with its nature and interactions largely unknown.
• Direct detection experiments aim to identify dark matter particles through their interactions with detector materials.
• Previous searches have primarily focused on higher mass dark matter candidates, leaving a gap for sub-MeV/c² particles.

Purpose of the Study:

• To establish the first germanium (Ge)-based constraints on sub-MeV/c² dark matter particles interacting with electrons.
• To investigate the potential of Ge cryogenic detectors for detecting low-energy electron signals induced by dark matter.
• To set limits on the dark matter-electron scattering cross-section and the kinetic mixing parameter of dark photons.

Main Methods:

• Utilized a 33.4 g Ge cryogenic detector with high energy resolution (0.53 electron-hole pair, rms).
• Operated the detector deep underground at the Laboratoire Souterrain de Modane to minimize background noise.
• Analyzed data to search for signals consistent with dark matter-electron interactions.

Main Results:

• Established the first Ge-based constraints for sub-MeV/c² dark matter particles interacting with electrons.
• Set competitive limits on the dark matter-electron scattering cross-section.
• Achieved the most stringent limits for dark photon dark matter in the 6 to 9 eV/c² mass range, down to 1 eV/c².

Conclusions:

• Ge cryogenic detectors are highly relevant for the search of eV-scale electron signals from dark matter.
• The study demonstrates the potential of this technology to probe previously unexplored dark matter parameter spaces.
• Future experiments with Ge detectors can further improve sensitivity to low-mass dark matter candidates.