Abstract

After important upgrades to the experiment, the Super-Kamiokande collaboration returns to measuring the solar mixing angle and the mass splitting $\mathrm{\ensuremath{\Delta}}\phantom{\rule{0}{0ex}}{m}_{12}^{2}$. By focusing on low-energy ${}^{8}B$ neutrinos, the collaboration is able to single out neutrinos that undergo flavor conversion only through vacuum oscillations. The results are the currently most precise values for the mixing and mass-difference parameters relevant for vacuum solar neutrino oscillations.