Exploring CEvNS with NUCLEUS at the Chooz Nuclear Power Plant

TL;DR

The paper presents the NUCLEUS experiment designed to detect CEvNS at the Chooz nuclear power plant using cryogenic detectors with low energy thresholds, aiming to explore neutrino properties and search for new physics.

Contribution

It introduces a new experimental setup with advanced detectors and background reduction techniques at a novel site for CEvNS measurement near reactors.

Findings

First background measurements at Chooz site

Feasibility of detector operation with muon veto at shallow depth

Promising sensitivity for neutrino physics studies

Abstract

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of (anti-)neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study CE$\nu$NS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low energy threshold and a time response fast enough to be operated in above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measure CE$\nu$NS of reactor antineutrinos. A new experimental site, denoted the Very-Near-Site (VNS) at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 GW$_{\mathrm{th}}$ reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental setup with dedicated active and passive background reduction techniques is presented. Furthermore, the feasibility to operate the NUCLEUS detectors in coincidence with an active muon-veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the promising physics potential of NUCLEUS at the Chooz nuclear power plant.