First results from T2K's upgraded near detector

Parallel talk presented at the XXI International Workshop on Neutrino Telescopes - Padova 29 September - 3 October 2025 (https://agenda.infn.it/event/44606/) On behalf of the T2K Collaboration Abstract: T2K is a long-baseline experiment measuring neutrino and antineutrino oscillations by observing the disappearance of muon neutrinos, as well as the appearance of electron neutrinos, over a long 295km distance. The ND280 near detector at J-PARC plays a crucial role to minimise the systematic uncertainties related to the neutrino flux and neutrino-nucleus cross-sections as it measures the neutrino beam at a ND site before it oscillates. The ND280 detector has recently been upgraded with a new suite of sub-detectors: a high granularity SuperFGD with 2 million optically-isolated scintillating cubes read out by wavelength shifting fibres and 55000 Multi-Pixel Photon Counters; two horizontal Time-Projection Chambers instrumented with resistive Micromegas, and additionally six panels of scintillating bars for precise time-of-flight measurements. These new detectors permit analyses with lower tracking thresholds, 4pi angular acceptance and the measurement of kinematics of neutrons produced in neutrino interactions. In this talk, new data using the upgraded ND280 detector configuration will be discussed, highlighting significant performance improvements.