Probing dark matter interactions with a RES-NOVA prototype cryogenic detector

TL;DR

This paper demonstrates a cryogenic PbWO4 detector's potential for dark matter searches, achieving low thresholds and setting exclusion limits, thus validating the RES-NOVA detection concept with archaeological lead crystals.

Contribution

It presents the first dark matter exclusion limits using a PbWO4 cryogenic detector and validates the RES-NOVA concept with archaeological lead, despite its small scale.

Findings

Achieved low energy threshold with a 13 g PbWO4 detector.

Derived dark matter exclusion limits for spin-dependent and independent interactions.

Proved effective vibration control and low noise in cryogenic conditions.

Abstract

We report on the operation of a 13 g PbWO$_4$ crystal, grown from archaeological Pb and operated as a cryogenic calorimeter in an underground environment. Read out with a Ge thermistor, the detector achieves a low energy threshold and, for the first time, enables the derivation of a dark matter exclusion limit using PbWO$_4$ as target material, for both spin-dependent interactions on neutrons and spin-independent interactions. Although limited in mass and not representative of the final RES-NOVA detector design, this prototype demonstrates effective control of mechanical vibrations and low-energy noise in a cryogenic system, which is a key requirement for rare-event searches. The experiment therefore provides a proof of principle for the RES-NOVA detection concept, validating the use of archaeological Pb-based PbWO$_4$ crystals, low-background operation, and robust data-analysis procedures. These results establish a solid technological and methodological foundation for future RES-NOVA detectors employing larger target masses and advanced thermal readout technologies.