First Constraints from DAMIC-M on Sub-GeV Dark-Matter Particles Interacting with Electrons

TL;DR

This paper presents new constraints on sub-GeV dark matter particles interacting with electrons, using DAMIC-M detectors' low noise CCDs to explore previously untested mass ranges and interaction parameters.

Contribution

It provides the first underground constraints on sub-GeV dark matter-electron interactions using DAMIC-M, covering new mass and mediator interaction parameter spaces.

Findings

Excluded new parameter space for dark matter masses 1.6 to 1000 MeV/c^2.

Set limits on ultralight and heavy mediator interactions.

Demonstrated DAMIC-M's low charge resolution for dark matter searches.

Abstract

We report constraints on sub-GeV dark matter particles interacting with electrons from the first underground operation of DAMIC-M detectors. The search is performed with an integrated exposure of 85.23 g days, and exploits the subelectron charge resolution and low level of dark current of DAMIC-M charge-coupled devices (CCDs). Dark-matter-induced ionization signals above the detector dark current are searched for in CCD pixels with charge up to 7e$^-$. With this dataset we place limits on dark matter particles of mass between 0.53 and 1000 MeV/$c^2$, excluding unexplored regions of parameter space in the mass ranges [1.6,1000] MeV/$c^2$ and [1.5,15.1] MeV/$c^2$ for ultralight and heavy mediator interactions, respectively.