COSINUS -- a model-independent challenge of the DAMA/LIBRA dark matter claim with cryogenic NaI detectors operated in a new low-background facility

TL;DR

COSINUS introduces a novel cryogenic NaI detector technology that combines scintillation and phonon detection for model-independent dark matter searches, aiming to verify DAMA/LIBRA's claims with reduced systematic uncertainties.

Contribution

The paper presents the development of a cryogenic NaI detector with dual readout for particle identification, enabling a new approach to test dark matter signals independently of models.

Findings

Designed and commissioned a low-background cryogenic facility at LNGS.

Plans to commence data collection with eight detectors in late 2025.

Unique dual-channel detection method enhances particle identification accuracy.

Abstract

Low-temperature detectors are a powerful technology for dark matter search, offering excellent energy resolution and low energy thresholds. COSINUS is the only experiment that combines scintillating sodium iodide (NaI) crystals with an additional phonon readout at cryogenic temperatures, using superconducting sensors (remoTES), alongside the conventional scintillation light signal. Via the simultaneous phonon and scintillation light detection, a unique event-by-event particle identification is enabled. This dual-channel approach allows for a model-independent cross-check of the long-standing DAMA/LIBRA signal with a moderate exposure of a few hundred kg d, while completely avoiding key systematic uncertainties inherent to scintillation-only NaI-based searches. COSINUS built and commissioned a dedicated low-background cryogenic facility at the LNGS underground laboratories. Data taking with eight NaI detector modules (COSINUS1$\pi$ Run1) is planned to begin in late 2025.