High significance measurement of reactor coherent elastic neutrino-nucleus scattering on germanium by CONUS+

We report the most precise measurement to date of coherent elastic neutrino-nucleus scattering (CE$ν$NS) from reactor antineutrinos using the CONUS+ high-purity germanium detectors at the Leibstadt nuclear power plant. With an exposure of 1296 kg$\cdot$days reactor-on, a blind likelihood analysis yields $1555 \pm 152$ CE$ν$NS events, with a significance of 10.2 $σ$, in agreement with the Standard Model expectation of $1701 \pm 198$ events within 0.6 standard deviations. The result also determines the weak mixing angle at a momentum transfer of about 10 MeV, $\sin^2θ_W = 0.225 \pm 0.022$, consistent with the Standard Model prediction.