Results and Progress from HVeV@CUTE

The SuperCDMS-HVeV (High-Voltage with eV resolution) program is an R&D project focused on developing detectors with low energy resolution to search for low-mass dark matter (< 1 GeV/c²), study charge-transport in cryogenically cooled crystals, and probe unclassified backgrounds at low energy. The program utilizes gram-scale silicon detectors instrumented with TES (transition-edge sensor)-based phonon sensors. A high-voltage bias can be applied to the crystal to amplify phonon signals from ionizing interactions via the Neganov-Trofimov-Luke effect. Utilizing these tools, HVeV detectors have recently achieved sub-eV baseline energy resolutions and demonstrated competitive sensitivities to electron-recoil dark matter at masses below 1 MeV/c². This talk will show results from a data-taking campaign conducted at the CUTE facility at SNOLAB using an HVeV detector with a sub-eV baseline resolution. Included in these results are observations of the Low Energy Excess and progress on an electron-recoil dark matter search.