First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB

We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2--30 eV c^-2 with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter κ is competitive with constraints from solar emission, reaching a minimum value of 2.2×10^-14 at 17 eV c^-2. These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses 3--12 eV c^-2 and the first demonstration of direct experimental sensitivity to ionization signals <12 eV from dark matter interactions.