The JHF-Kamioka neutrino experiment

We propose the JHF-Kamioka neutrino experiment to study the mass and mixing of leptons to great precision through neutrino oscillation. The experiment uses a high intensity narrow-band neutrino beam produced by JHF, Japan Hadron Facility, and the world largest water Cherenkov detector, Super-Kamiokande. The main physics goals are: (1) to discover νμ→νe oscillation with a mixing angle, θ13, down to 0.006, (2) to measure the oscillation parameters in νμ→νμ oscillation with a precision of 1% for the mixing angle and 10−4eV2 for the mass square difference, and (3) to confirm νμ→ντ or to eliminate νμ→νs by measuring the neutral current events. The experiment can extend the physics potential to measure CP violation in neutrino oscillation for the CP-violation phase (δ) down to 10–20°, by upgrading the JHF accelerator to 4 MW and by constructing a new 1 Mton water Cherenkov detector, Hyper-Kamiokande. The experiment is planned to start in 2007 at the same time of completing the JHF accelerator complex.