Updated T2K measurements of muon neutrino and antineutrino disappearance using 1.5 × 10~(21) protons on target

摘要

We report measurements by the T2K experiment of the parameters θ_(23) and Δm_(32)~2 governing the disappearance of muon neutrinos and antineutrinos in the three-flavor neutrino oscillation model. Utilizing the ability of the experiment to run with either a mainly neutrino or a mainly antineutrino beam, the parameters are measured separately for neutrinos and antineutrinos. Using 7.482 × 10~(20) POT in neutrino running mode and 7.471 × 10~(20) POT in antineutrino mode, T2K obtained sin~2(θ_(23)) = 0.51_(-0.07)~(+0.08) and Δm_(32)~2 = 2.53_(-0.13)~(+0.15) × 10~(-3) eV~2/c~4 for neutrinos, and sin~2(θ_(23)) = 0.42_(-0.07)~(+0.25) and Δm~2_(32) = 2.55_(-0.27)~(+0.33) × 10~(-3) eV~2/c~4 for antineutrinos (assuming normal mass ordering). No significant differences between the values of the parameters describing the disappearance of muon neutrinos and antineutrinos were observed.