Spectral Measurement of the Electron Antineutrino Oscillation Amplitude and Frequency using 500 Live Days of RENO Data

Published 14 Oct 2016 in hep-ex and physics.ins-det | (1610.04326v7)

Abstract: The Reactor Experiment for Neutrino Oscillation (RENO) has been taking electron antineutrino ($\overline{\nu}{e}$) data from the reactors in Yonggwang, Korea, using two identical detectors since August 2011. Using roughly 500 live days of data through January 2013 we observe 290,775 (31,514) reactor $\overline{\nu}{e}$ candidate events with 2.8 (4.9)% background in the near (far) detector. The observed visible positron spectra from the reactor $\overline{\nu}{e}$ events in both detectors show discrepancy around 5 MeV with regard to the prediction from the current reactor $\overline{\nu}{e}$ model. Based on a far-to-near ratio measurement using the spectral and rate information we have obtained $\sin² 2 \theta_{13} = 0.082 \pm 0.009({\rm stat.}) \pm 0.006({\rm syst.})$ and $|\Delta m_{ee}^2| =[2.62_{-0.23}^{+0.21}({\rm stat.})_{-0.13}^{+0.12}({\rm syst.})]\times 10^{{-3}$eV$^2$.}