Wider research context
The search for dark matter (DM) is on the title page of particle physics, as there is overwhelming astronomical and cosmological evidence for its existence but no insight into its fundamental nature. Direct DM searches aim to observe interactions of potential DM particles with earth-bound detectors. Many technologies are employed for this search which is necessary due to the a-priori unknown mass(es) of the DM particle(s).
Research questions
Cryogenic detectors are the favorite technology for masses in the MeV - GeV range, however, they are facing a fundamental dilemma: on the one hand, the target crystals need to be small to achieve the required low thresholds. On the other hand, large target masses are necessary to gain high sensitivity for rare DM interactions. The way out of this dilemma are large arrays of small cryogenic detectors. However, such arrays impose challenges from analyzing large raw data sets to statistical inference methods which we will face in ALCDA.
Approach
ALCDA is embedded in the cryogenic DM searches CRESST and COSINUS, both placed in the LNGS underground laboratory in Italy. CRESST is a leading experiment in the search for light DM and will upgrade the number of readout channels from 30 to 288 in 2024/25. COSINUS is a new cryogenic direct DM search to start in 2024 with a maximum of 48 readout channels. The goal of COSINUS is a model-independent crosscheck of the disputed DM claim put forward by the DAMA/LIBRA collaboration. Both experiments rely on ALCDA to achieve the best possible DM results.
Beyond CRESST and COSINUS, the ALCDA developments may also be applied in the NUCLEUS experiment. NUCLEUS is based on the same technology but investigates coherent elastic neutrino- nucleus scattering. It is based at the Chooz nuclear power plant in France and will start data-taking in 2024.
For ALCDA, we follow a three-stage approach. Firstly, we will thoroughly review the existing analysis tools as a basis for making them fit for the analysis of large detector arrays. Secondly, we will expand our likelihood framework for statistical inference. Third, we will apply our developments to data from CRESST and COSINUS and produce highly visible DM results that may be expected within the project timeline.
Innovation
ALCDA will develop and use the necessary tools to fully harvest the data from upcoming large cryogenic detector arrays for direct DM detection and neutrino physics. Primary researchers involved ALCDA will be performed at the joint research group of TU Wien and HEPHY whose main expertise and involvement is data analysis for CRESST, COSINUS and NUCLEUS. Florian Reindl, the PI of ALCDA, is the spokesperson of COSINUS and former analysis coordinator of CRESST. The national research partner is Jochen Schieck, Director of HEPHY and the HEPHY/TU Wien group leader. Additional support will be provided by the MPP for physics in Munich with the
