Measurement of Reactor Antineutrino Oscillation Amplitude and Frequency at RENO

Abstract

The RENO experiment reports more precisely measured values of theta(13) and vertical bar Delta m(ee)(2)vertical bar using similar to 2200 live days of data. The amplitude and frequency of reactor electron antineutrino ((nu) over bar (e)) 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) (nu) over bar (e) candidate events with a background fraction of 4.8% (2.0%). A clear energy and baseline dependent disappearance of reactor (nu) over bar (e) is observed in the deficit of the measured number of (nu) over bar (e). Based on the measured far-to-near ratio of prompt spectra, we obtain sin(2)2 theta(13) = 0.0896 +/- 0.0048(stat) +/- 0.0047(syst) and vertical bar Delta m(ee)(2)vertical bar = [2.68 +/- 0.12(stat) +/- 0.07(syst)] x 10(-3) eV(2).