Measurement of Reactor Antineutrino Oscillation Amplitude and Frequency at RENO

The RENO experiment reports more precisely measured values of θ₁₃ and |Δmₑₑ²| using ~2200 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 sin²2θ₁₃=0.0896±0.0048(stat)±0.0047(syst) and $|{{Δ}}{m}ₑₑ²|={{0ex}{0ex}}[2.68±{}0.12(stat)±{}0.07(syst)]×{}{10}^{{-}3} {eV}²$.