Speaker
Description
The T2K neutrino oscillation experiment employs a near detector (ND280) close to neutrino production to reduce systematic uncertainties associated with the neutrino flux and interaction cross-section models. A significant upgrade of the near detector was completed in 2024. The new active neutrino target, the SuperFGD, consists of around two million optically isolated plastic scintillator cubes with 1 cm side length. High-Angle Time Projection Chambers (HA-TPCs) above and below the SuperFGD improve particle identification and momentum reconstruction for exiting tracks. Six Time-of-Flight (ToF) plastic scintillator planes surround the SuperFGD and HA-TPCs, providing fast timing for track direction determination and background rejection. With the detector response characterized and calibrated using control samples, detector systematic uncertainties have been evaluated and the upgraded detector is now delivering first physics results.
This poster presents the latest progress in the analysis of muon neutrino charged-current pion-less (CC0$\pi$) interactions within the SuperFGD. As the dominant interaction topology at T2K neutrino energies, these samples will be central in constraining the relevant systematic uncertainties, in particular as the statistical uncertainties become sub-dominant. The sub-samples with muons reconstructed in the HA-TPCs allow for improved precision in the kinematic region of large four-momentum transfer squared $Q^2$. This is particularly important to increase the phase space overlap with the far detector, Super-Kamiokande. The near detector upgrade also enables improved reconstruction of proton kinematics. The 3D readout in the SuperFGD results in almost isotropic acceptance and improved tracking thresholds compared to the original ND280, as demonstrated in the CC0$\pi$ samples shown here. Measurements of cross sections in observables constructed from proton kinematics, such as transverse kinematic imbalances, will allow for novel insights into neutrino-nucleus interactions in the future.