Faculty of Mathematics, Physics
and Informatics
Comenius University Bratislava

Dark matter search

Dark matter is a not-yet-identified form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total energy density. A large number of dark matter studies, from theory to direct dark matter particle detection, involve nuclear physics and particle physics. Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light - making it hard to detect. We think it only interacts with other matter (and itself) via gravity, but dark matter could turn out to have interactions with any force of nature - known or unknown.


 

There is no short age of ideas as to what the dark matter could be. Among the non-baryonic candidates there are several classes of particles, e.g. WIMPs, axion, sterile neutrino etc. Experiments searching for dark matter candidates can be divided into 3 classes: direct, indirect and collider searches. Direct detection experiments search for the scattering of dark matter particles off atomic nuclei within a detector assuming such particles pass through Earth. In indirect detection, we look for the products of dark matter particle - assuming these particles can undergo annihilation interactions with themselves, possibly resulting in observable by-products such as gamma rays and neutrinos. An alternative approach to the detection of dark matter particles is to produce them in colliders, where they may be detected indirectly as missing energy and momentum that escape the detectors, provided other collision products are detected.


Ways of dark matter detection (DM - dark matter, SM - standard matter)

CRESST

(Cryogenic Rare Event Search with Superconducting Thermometers)
CRESST uses cryogenic CaWO4 crystal scintillating calorimeters for direct dark matter searches in Gran Sasso underground laboratory in Italy. A cryogenic calorimeter consists of an absorber and a temperature sensor in thermal contact - particle interactions via their elastic scattering off nuclei of absorber can heat up the detectors strongly enough in order to be detected.