New constraints on physics within and beyond the standard model from the latest CONUS datasets

TL;DR

The CONUS experiment uses germanium detectors near nuclear reactors to measure neutrino interactions, providing new constraints on physics beyond the Standard Model and confirming SM predictions with high significance.

Contribution

This work presents the first observation of CEνNS at Leibstadt, improves limits on neutrino magnetic moment and millicharge, and refines constraints on NSIs and the Weinberg angle.

Findings

Observation of CEνNS with 3.7σ significance at Leibstadt

Improved limits on neutrino magnetic moment and millicharge

Refined constraints on NSIs and measured the Weinberg angle

Abstract

Its detections with pion-decay-at-rest, solar and recently with reactor antineutrinos by the CONUS collaboration render coherent elastic neutrino-nucleus scattering (CE$\nu$NS) an established tool for investigations within and beyond the Standard Model (SM). The CONUS experiment located at the nuclear power plants in Brokdorf (Germany) and Leibstadt (Switzerland) operates Germanium semiconductor detectors in a compact shield at close distance to the reactor core. An observation with $3.7 \sigma$ significance is reported at the Leibstadt site, showing good agreement with its SM prediction. Physics investigations performed with the last datasets collected at the Brokdorf reactor and with the first data obtained at the Leibstadt site are summarized. By using the experimental analysis framework, the presented results contain the full systematics that underlie the experiment. Previously determined limits with neutrino-electron scattering on the neutrino magnetic moment and a neutrino millicharge are improved to $\mu_{\nu} <5.18\cdot 10^{-11}\mu_\mathrm{B}$ and $q_{\nu}<1.76\cdot 10^{-12} e_0$ (90% C.L). Further, the scale of new physics related to NSIs is improved to $\Lambda_{\rm NSI}$=145 GeV and limits on the coupling of light new mediators are lowered down to $4 \cdot 10^{-7}$ (90% C.L.) with the new data. Finally, the determination of the Weinberg angle with CE$\nu$NS and reactor antineutrinos yields $\sin^{2}\theta_W= 0.28^{+0.03}_{-0.04}$ at a momentum transfer of $\sim 10 \ \mathrm{MeV}$.