Measurement of reactor antineutrino oscillation amplitude and frequency using 3800 days of complete data sample of the RENO experiment

We report an updated neutrino mixing angle of ${\theta }_{13}$ obtained from a complete data sample of the RENO experiment. The experiment has measured the amplitude and frequency of reactor anti-electron-neutrinos (${\bar{\nu }}_e$) 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 (IBD) are 1,211,995 (144,667) in the near (far) detector. Based on an observed energy-dependent reactor neutrino disappearance, neutrino oscillation parameters of ${\theta }_{13}$ and $\mid \mathrm{\Delta }{m}_{ee}^2\mid$ are precisely determined as ${\sin }^{2}2{\theta }_{13}=0.0920_{-0.0042}^{+0.0044}(\text{stat.}{)}_{-0.0041}^{+0.0041}(\text{syst.})$ and $\mid \mathrm{\Delta }{m}_{ee}^2\mid =[2.57_{-0.11}^{+0.10}(\text{stat.}{)}_{-0.05}^{+0.05}(\text{syst.})]\times {10}^{-3}{\text{eV}}^2$. Compared to the previous RENO results published in Ref.~\cite{PhysRevLett.121.201801}, the precision is improved from 7.5% to 6.4% for ${\sin }^{2}2{\theta }_{13}$ and from 5.2% to 4.5% for $\mid \mathrm{\Delta }{m}_{ee}^2\mid$. The statistical error of the measurement has reached our goal and is hardly improved with additional data-taking.