Measurement of reactor antineutrino oscillation parameters using the full 3800-day dataset of the RENO experiment

초록

We report an updated neutrino mixing angle of 013 obtained from a complete data sample of the RENO experiment. The experiment has measured the amplitude and frequency of reactor electron antineutrino (Ue) oscillations at the Hanbit nuclear power plant, Younggwang, Korea, since August 2011. As of March 2023, the data acquisition was completed after a total of 3800 live days of detector operation. The observed candidates via inverse beta decay with the neutron capture on the gadolinium channel are 1,211,995 (144,667) in the near (far) detector. Based on an observed energy-dependent reactor neutrino disappearance, neutrino oscillation parameters of 013 and IOm2eeI are precisely determined as sin22013 = 0.0920-0.0044-0.0042 (stat)+0.0041-0.0041 (syst) and IOm2eeI = [2.57-0.10-0.11 (stat)-0.05-0.05 (syst)] x 10-3 eV2. Compared to the previously published RENO results, the precision is improved from 7.5% to 6.4% for sin2 2013 and from 5.2% to 4.5% for IOm2eeI. The statistical error of the measurement has reached our goal and is hardly improved with additional data taking.