Speaker
Description
The Cryogenic Rare Event Search with Superconducting Thermometers (CRESST), located at the Laboratori Nazionali del Gran Sasso (INFN, Italy), targets the direct detection of sub-GeV dark matter (DM) via nuclear recoils in cryogenic CaWO$_4$ detectors instrumented with tungsten Transition Edge Sensors (W-TES). Operating at millikelvin temperatures, these detectors combine phonon and light readout to achieve nuclear recoil energy thresholds at the $\mathcal{O}$(10–30 eV) level, enabling world-leading sensitivity to DM particles with masses below 1.7 GeV/$c^2$.
At the lowest energies, CRESST observes a steeply rising population of events below 200 eV, referred to as the Low Energy Excess (LEE), which currently sets the dominant limitation on sensitivity. The recently developed DoubleTES approach, based on the coincident readout of two TES sensors on a single absorber, provides, for the first time, a handle to identify and possibly mitigate this excess.
Combined with targeted optimisations of the TES design and operating conditions, these developments lead to improved signal-to-noise performance and enhanced background rejection. We present the latest results on LEE mitigation together with the most recent constraints on light dark matter interactions.