Measurement of Reactor Antineutrino Oscillation at SNO+

Abstract

SNO+ Collaboration reports its second spectral analysis of reactor antineutrino oscillation using 286 ton-yr of new data. The measured energies of reactor antineutrino candidates were fitted to obtain the second-most precise determination of the neutrino mass-squared difference Δm212=(7.96-0.42+0.48)×10-5 eV2. Constraining Δm212 and sin2θ12 with measurements from long-baseline reactor antineutrino and solar neutrino experiments yields Δm212=(7.58-0.17+0.18)×10-5 eV2 and sin2θ12=0.308±0.013. This fit also yields a first measurement of the flux of geoneutrinos in the Western Hemisphere, with 73-43+47 TNU at SNO+.