Updated T2K measurements of muon neutrino and antineutrino disappearance using 1.5×10[21] protons on target

We report measurements by the T2K experiment of the parameters θ23 and Δm\ud 2\ud 32 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 7.482×1020 POT in neutrino running mode and 7.471×1020 POT in antineutrino mode, T2K obtained sin2(θ23)=0.51\ud +0.08\ud −0.07 and Δm\ud 2\ud 32=2.53\ud +0.15\ud −0.13×10−3 eV2/c4 for neutrinos, and sin2(\ud ¯\ud θ23)=0.42\ud +0.25\ud −0.07 and Δ\ud ¯\ud m232=2.55\ud +0.33\ud −0.27×10−3 eV2/c4 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.