The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six 2.8  GW(th) reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is 0.920±0.009(stat)±0.014(syst). From this deficit, we determine sin(2)2θ(13)=0.113±0.013(stat)±0.019(syst) based on a rate-only analysis.

The RENO experiment reports more precisely measured values of θ13 and |∆m 2 ee | using ∼2 200 live days of data. The amplitude and frequency of reactor electron antineutrino (νe) oscillation are measured by comparing the prompt signal spectra obtained from two identical near and far detectors. In the period between August 2011 and February 2018, the far (near) detector observed 103 212 (850 666) νe candidate events with a background fraction of 4.8% (2.0%). A clear energy and baseline dependent disappearance of reactor νe is observed in the deficit of the measured number of νe. Based on the measured far-to-near ratio of prompt spectra, we obtain sin 2 2θ13 = 0.0896 ± 0.0048(stat) ± 0.0047(syst) and |∆m 2 ee | = [2.68 ± 0.12(stat) ± 0.07(syst)] × 10 −3 eV 2 .

The Reactor Experiment for Neutrino Oscillation (RENO) has been taking electron antineutrino (ν 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) reactorν e candidate events with 2.8% (4.9%) background in the near (far) detector. The observed visible positron spectra from the reactorν e events in both detectors show a discrepancy around 5 MeV with regard to the prediction from the current reactorν e model. Based on a far-to-near ratio measurement using the spectral and rate information, we have obtained sin 2 2θ 13 ¼ 0.082 AE 0.009ðstat:Þ AE 0.006ðsyst:Þ and jΔm

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