Rare Event Searches Using Cryogenic Detectors via Direct Detection Methods

TL;DR

Cryogenic detectors enable direct detection of extremely rare processes by delivering ultra-low energy thresholds and high-resolution readouts across phonon-, ionization-, and scintillation-channel modalities. The paper catalogs major experiments probing WIMPs, ALPs, dark photons, FCPs, CEνNS, and 0νββ, highlighting how sub-GeV sensitivity is achieved and how multi-channel readouts improve background rejection. Key challenges include quenching-factor uncertainties, low-energy calibration, and irreducible neutrino backgrounds, while next-generation efforts (e.g., CUPID, LEGEND, nEXO, NUCLEUS, Ricochet) promise to extend reach into previously inaccessible parameter space. Overall, cryogenic detectors are poised to play a central role in probing fundamental questions about dark matter, neutrino properties, and lepton-number-violating processes in the coming decade.

Abstract

Cryogenic detectors are at the forefront of rare-event search experiments, including direct detection of dark matter, coherent elastic neutrino-nucleus scattering, neutrinoless double-beta decay, and searches for fractionally charged particles. Their unique ability to achieve ultra-low energy thresholds, typically O(eV-100 eV), together with excellent energy resolution and effective background suppression, makes them sensitive to extremely faint signals from rare interactions. These rare particle interactions produce phonons, ionization, or scintillation, depending on the target medium, which are registered by specialized sensors and converted into measurable signals. This review summarizes the underlying detection principles, surveys major experiments and recent results, examines forthcoming initiatives, and outlines the evolving role of cryogenic detectors in advancing the frontiers of rare-event physics.

Figures (9)

• Figure 1: Venn diagram of direct detection experiments, based on the signal detection: phonons or heat (yellow), scintillation or light (blue), and ionization or charge (orange).
• Figure 2: (a) A Schematic diagram of a phonon-based cryogenic detector with TES sensor. (b) Typical TES transition: Resistance vs Temperature near $\mathrm{T_{C}}$.
• Figure 3: The High Voltage eV-scale detector used by SuperCDMS hvevSuperCDMS_SNOALB_SNOWMASS_2021. (b) A p-type point-contact (PPC) Ge detector, labels C1–C5 are explained in the reference ppc. (c) A cryogenic detector at CUPID that measures scintillation and phonon signals cupid_det.
• Figure 4: Theoretically motivated dark matter candidates discussed in this article, along with their expected mass ranges and corresponding detection strategies.
• Figure 5: 90% confidence level upper limits on the WIMP--nucleon scattering cross section from SuperCDMS CDMSliteR2_WIMPCDMSliteR3_WIMP_PLR_2019SuperCDMS_migdal_Brem_WIMP_2023, EDELWEISS EDELWEISS_WIMP_2019EDELWEISS_migdal_2022, TESSERACT TESSERACT:2025tfw, PICO PICO_WIMP_2019, DarkSide DarkSide_2023_QF_WIMP_with_migdal, CRESST CRESST_2019_WIMPCRESST_2024_WIMP, LZ LZ_2023_WIMP, PandaX PandaX_2025_WIMP, and XENON XENONnT_2025_WIMP, together with the neutrino floor for germanium targets Billard:2021_APPEC_report_neutrino_floor_Ge. Below 0.06 GeV/$c^{2}$, published calculations of the neutrino floor are unavailable, as they would require unrealistically low thresholds ($\mathcal{O}$(meV) or less) for Ge detectors and rely on uncertain low-energy neutrino flux predictions. Experiments such as CRESST and SuperCDMS dominate the low-mass regime, while dual-phase TPC experiments such as XENON, LZ, and PandaX set the most stringent limits at higher masses. Experimental limits are taken from public data or digitized from published figures.