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Models for light dark matter particles with masses below 1 GeV/c 2 are a natural and well-motivated alternative to so-far unobserved weakly interacting massive particles. Gram-scale cryogenic calorimeters provide the required detector performance to detect these particles and extend the direct dark matter search program of CRESST. A prototype 0.5 g sapphire detector developed for the ν -cleus experiment has achieved an energy threshold of E t h = ( 19.7 ± 0.9 )  eV. This is one order of magnitude lower than for previous devices and independent of the type of particle interaction. The result presented here is obtained in a setup above ground without significant shielding against ambient and cosmogenic radiation. Although operated in a high-background environment, the detector probes a new range of light-mass dark matter particles previously not accessible by direct searches. We report the first limit on the spin-independent dark matter particle-nucleon cross section for masses between 140 and 500 MeV/c 2 .

The CRESST-II experiment uses cryogenic detectors to search for nuclear recoil events induced by the elastic scattering of dark matter particles in CaWO 4  crystals. Given the low energy threshold of our detectors in combination with light target nuclei, low mass dark matter particles can be probed with high sensitivity. In this letter we present the results from data of a single detector module corresponding to 52 kg live days. A blind analysis is carried out. With an energy threshold for nuclear recoils of 307 eV we substantially enhance the sensitivity for light dark matter. Thereby, we extend the reach of direct dark matter experiments to the sub- GeV/ c 2  region and demonstrate that the energy threshold is the key parameter in the search for low mass dark matter particles.

Models for light dark matter particles with masses below 1 GeV/c [Formula omitted] are a natural and well-motivated alternative to so-far unobserved weakly interacting massive particles. Gram-scale cryogenic calorimeters provide the required detector performance to detect these particles and extend the direct dark matter search program of CRESST. A prototype 0.5 g sapphire detector developed for the [Formula omitted]-cleus experiment has achieved an energy threshold of [Formula omitted] eV. This is one order of magnitude lower than for previous devices and independent of the type of particle interaction. The result presented here is obtained in a setup above ground without significant shielding against ambient and cosmogenic radiation. Although operated in a high-background environment, the detector probes a new range of light-mass dark matter particles previously not accessible by direct searches. We report the first limit on the spin-independent dark matter particle-nucleon cross section for masses between 140 and 500 MeV/c [Formula omitted].

Identifying the nature and origin of dark matter is one of the major challenges for modern astro and particle physics. Direct dark-matter searches aim at an observation of dark-matter particles interacting within detectors. The focus of several such searches is on interactions with nuclei as provided e.g. by weakly interacting massive particles. However, there is a variety of dark-matter candidates favoring interactions with electrons rather than with nuclei. One example are dark photons, i.e., long-lived vector particles with a kinetic mixing to standard-model photons. In this work we present constraints on this kinetic mixing based on data from CRESST-II Phase 2 corresponding to an exposure before cuts of 52 kg-days. These constraints improve the existing ones for dark-photon masses between 0.3 and 0.7 keV/c 2 .

In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a \\[\\hbox {Li}_2\\hbox {MoO}_4\\] target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between \\[0.8~\\hbox {GeV/c}^2\\] and \\[1.5~\\hbox {GeV/c}^2\\].

The CRESST experiment (Cryogenic Rare Even Search with Superconducting Thermometers), located at Laboratori Nazionali del Gran Sasso in Italy, searches for dark matter particles via their elastic scattering off nuclei in a target material. The CRESST target consists of scintillating CaWO4 crystals, which are operated as cryogenic calorimeters at millikelvin temperatures. Each interaction in the CaWO4 target crystal produces a phonon signal and a light signal that is measured by a second cryogenic calorimeter. Since the CRESST-II result in 2015, the experiment is leading the field of direct dark matter search for dark matter masses below 1.7 GeV/c2, extending the reach of direct searches to the sub-GeV/c2 mass region. For CRESST-III, whose Phase 1 started in July 2016, detectors have been optimized to reach the performance required to further probe the low-mass region with unprecedented sensitivity. In this contribution the achievements of the CRESST-III detectors will be discussed together with preliminary results and perspectives of Phase 1.

CRESST is a direct dark matter search experiment, aiming for an observation of nuclear recoils induced by the interaction of dark matter particles with cryogenic scintillating calcium tungstate crystals. Instead of confining ourselves to standard spin-independent and spin-dependent searches, we re-analyze data from CRESST-II using a more general effective field theory (EFT) framework. On many of the EFT coupling constants, improved exclusion limits in the low-mass region (< 3–4 GeV/\\[c^2\\]) are presented.

The CRESST experiment uses cryogenic detectors based on transition-edge sensors to search for dark matter interactions. Each detector module consists of a scintillating CaWO 4 crystal and a silicon-on-sapphire (SOS) light detector which operate in coincidence (phonon-light technique). The 40-mm-diameter SOS disks (2 g mass) used in the data taking campaign of CRESST-II Phase 2 (2014–2016) reached absolute baseline resolutions of σ = 4–7 eV. This is the best performance reported for cryogenic light detectors of this size. Newly developed silicon beaker light detectors (4 cm height, 4 cm diameter, 6 g mass), which cover a large fraction of the target crystal surface, have achieved a baseline resolution of σ = 5.8 eV. First results of further improved light detectors developed for the ongoing low-threshold CRESST-III experiment are presented.

Cryogenic rare event searches based on heat and light composite calorimeters have a common need for large area photon detectors with high quantum efficiency, good radiopurity and high sensitivity. By employing the Neganov–Trofimov–Luke effect, the phonon signal of particle interactions in a semiconductor absorber operated at cryogenic temperatures can be amplified by drifting the photogenerated electrons and holes in an electric field. We present here the most recent results of a Neganov–Trofimov–Luke effect light detector with an electric field configuration optimized to improve the charge collection within the absorber.

The Physics Department of the Technical University of Munich operates a shallow underground detector laboratory in Garching, Germany. It provides ∼ 160 m 2 of laboratory space which is shielded from cosmic radiation by ∼ 6 m of gravel and soil, corresponding to a shielding of ∼ 15 m . w . e . . The laboratory also houses a cleanroom equipped with work- and wetbenches, a chemical fumehood as well as a spin-coater and a mask-aligner for photolithographic processing of semiconductor detectors. Furthermore, the shallow underground laboratory runs two high-purity germanium detector screening stations, a liquid argon cryostat and a 3 He– 4 He dilution refrigerator with a base temperature of ≤ 12 - 14 mK . The infrastructure provided by the shallow laboratory is particularly relevant for the characterization of CaWO 4 target crystals for the CRESST-III experiment, detector fabrication and assembly for rare event searches. Future applications of the laboratory include detector development in the framework of coherent neutrino nucleus scattering experiments ( ν -cleus) and studying its potential as a site to search for MeV-scale dark matter with gram-scale cryogenic detectors.