Coherent neutrino-nucleus scattering (CEvNS) is moving frontiers in low-energy neutrino physics.The NUCLEUS reactor-neutrino experiment, which uses cryogenic detectors with energy threshold of a few 10's of eV to detect CEvNS, will serve as a touchstone to search for new physics beyond current knowledge. CEvNS is a weak neutral-current process that has been first proposed in the 1970's as part of the Standard Model of Particle Physics (SM). This new interaction channel opens up a new chapter in neutrino physics. It will address important open questions concerning the interaction and the nature of neutrinos, and has the potential to discover new physics beyond the SM. Further, the technological advances might lead to interesting applications for nuclear non-proliferation. In the framework of project NU-CLEUS the required detector technology has been demonstrated: The world-best energy threshold for nuclear recoils of 19.7+-0.8eV has been achieved with the NUCLEUS detectors, which are single crystals (Al2O3, CaWO4) with a mass of about 1g. The detectors are operated as cryogenic detector at mK temperatures equipped with transition-edge-sensors, a technology that has been pioneered by the CRESST experiment.
In the ERC project NU-CLEUS there is a strong focus on the development and commissioning of the NUCLEUS10g detector at TUM, which is expected to be installed at the nuclear power plant in CHOOZ, France, in 2023. Based on the successful ERC StG application we have built up an international collaboration consisting of about 50 members with significant additional resources for the project. PI Strauss is the spokesperson of the NUCLEUS collaboration. The significantly increased manpower allows to achieve the scientific goals in a competitive manner, such that the experiment is on track to be the first experiment observing CEvNS at reactors.
