Speaker
Description
The NUCLEUS experiment aims to measure coherent elastic neutrino–nucleus scattering (CEνNS) at unprecedented low nuclear recoil energies using gram‑scale cryogenic calorimeters operated at the Chooz nuclear power plant. With energy thresholds at the O(10 eV) scale, NUCLEUS will probe CEνNS at extremely low momentum transfer, opening a new window for precision tests of the Standard Model and searches for new physics.
In this contribution, I will present sensitivity projections for the upcoming NUCLEUS Technical and Physics Runs, based on a realistic detector model and a data‑driven treatment of the low‑energy excess observed during commissioning. A likelihood framework exploiting reactor power modulation is developed to disentangle signal and background in a low signal‑to‑background regime and to assess the impact of dominant systematic uncertainties.
For the Technical Run with a 7 g CaWO₄ target, NUCLEUS achieves competitive sensitivity to several beyond‑the‑Standard‑Model scenarios without requiring a direct CEνNS observation. For the Physics Run, assuming suppression of the low‑energy excess, we project a 4.7σ observation of CEνNS within one year, enabling measurements of the weak mixing angle at low energy and leading constraints on the neutrino charge radius and new mediator models.