Measuring the CP-Violating Phase by a Long-BaseLine Neutrino Experiment with Hyper-Kamiokande(Joint Semenar (Kyoto University and this workshop),Flavor Mixing, CP Violation and Origin of Matter)

Abstract

In this talk, we show the sensitivity of a Long-Base-Line neutrino oscillation experiment between High Intensity Proton Accelerator (HIPA) and Hyper-Kamiokande, 295km away from HIPA, with conventional low energy neutrino beams to measure the CP phase in the lepton sector. CP violation in the lepton sector can be established at 4σ (3σ) level if the MSW large-mixing-angle scenario of the solar-neutrino deficit is realized, |δ_<MNS>| or |δ_<MNS>-180°|>30°, and if 4|U_<e3>|^2(1-|U_<e3>|^2) ≡ sin^22θ_<CHOOZ> > 0.03 (0.01). The phase δ_<MNS> is more difficult to constrain by this experiment if there is little CP violation, δ_<MNS>〜0° or 180°, which can be distinguished at 1σ level if sin^22θ_<CHOOZ>&gsim;0.01.