T2K future prospects with J-PARC neutrino beam and near detector upgrades

The long baseline neutrino experiment, Tokai-to-Kamioka (T2K), has obtained a first hint on matter-antimatter asymmetry in neutrino oscillations. Leptonic CP conservation was excluded at the 95% level with 2.2×10²¹ protons on target. To reach 3σ sensitivity for maximum violation in the search, T2K proposed a run extension until 2026 along with a higher intensity beam after the J-PARC Main Ring upgrade. Moreover, it has two major upgrade programs to be implemented in the next several years. One is an upgrade of the neutrino beamline to accept the high intensity proton beam up to 1.3 MW and to enhance the neutrino flux with a higher current in the electromagnetic horns. Another is an upgrade of the T2K near detector ND280. The goal is to reduce systematic uncertainties to less than 4% for the number of predicted events at the far detector. The current status and future prospects of those upgrades are presented. (author)