Dark matter-electron scattering search using cryogenic light detectors

The cryogenic scintillating calorimeter technology devoted to rare event searches is reaching the sensitivity level required for the hunt of dark matter-electron scatterings. Dark matter-electron interactions in scintillating targets are expected to stimulate the emission of single photons, each of energy equal to the target electronic band gap. The electronic band gap in scintillators like <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>NaI</a:mi><a:mo>/</a:mo><a:mi>GaAs</a:mi></a:mrow></a:math> is of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi mathvariant="script">O</c:mi><c:mo stretchy="false">(</c:mo><c:mi>eV</c:mi><c:mo stretchy="false">)</c:mo></c:math>. The search for this signal can be done by an array of cryogenic light detectors with <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mrow><h:mi>eV</h:mi><h:mo>/</h:mo><h:mi>sub</h:mi><h:mtext>−</h:mtext><h:mi>eV</h:mi></h:mrow></h:math> energy resolution. In this work, we describe the detection principle, the detector response, and the envisioned detector design to search for dark matter interacting with electrons via the measurement of the scintillation light at millikelvin. First sensitivity projections are provided, which show the potential of this research. Published by the American Physical Society 2024