Nucleus: Searching for Coherent Neutrino Nucleus Scattering at Lowest Energies

Coherent neutrino-nucleus scattering is a promising new tool in the toolbox of electroweak precision measurements at low q-transfer. It will enable precise measurements of standard model (SM) physics like the running of the Weinberg angle but also the search for new physics beyond the SM like sterile neutrinos. The Nucleus experiment aims at the first detection of fully coherent neutrino-nucleus scattering at the Chooz power plant in France, using its two 4GWth reactor cores as high-intensity source for anti-neutrinos. For this endeavour a new experimental site, the Very Near Site (VNS), with a shallow rock overburden of $$\approx {3}$$ m w.e. is under development. To be competitive in this challenging environment, Nucleus developed the novel concept of fiducialised cryogenic bolometers based on CaWO $$_4$$ monocrystals operated at $$\mathscr {O}$$ (10 mK). The signature of a coherent neutrino-nucleus scattering is a nuclear recoil at the 10 eV-scale. Currently, Nucleus is preparing its first phase with 10 g of target mass at the VNS. In this contribution, we will first introduce Nucleus, report its current state and give an outlook to its future.