The T2K experiment in Japan is a long-baseline neutrino oscillation experiment that aims to investigate CP violation in the leptonic sector. To enhance the precision of measurements related to the CP-violating phase (𝛿CP), the Near Detector complex (ND280) has undergone a major upgrade. A key component of this upgrade is the installation of new High-Angle Time Projection Chambers (HA-TPCs), designed to provide nearly full angular coverage (4π acceptance) and improved tracking of charged particles produced in neutrino interactions.
The HA-TPCs were installed at the J-PARC site during Autumn 2023 and Spring 2024. After commissioning with cosmic rays and initial neutrino beam tests, the detectors began collecting physics data in June 2024. Using the ND280 reconstruction software, the data are analysed to evaluate the initial performance of the HA-TPCs in terms of spatial, energy, and momentum resolution and studies on the electric field.
This talk will provide an overview of the ND280 upgrade and present the first performance results of the HA-TPCs, along with a brief outlook on their role in the upcoming Hyper-Kamiokande project.
Giada Caneva, Elia Bertoldo, Francesco Sciotti