# NuFact 2022: The 23rd International Workshop on Neutrinos from Accelerators

July 30, 2022 to August 6, 2022
Cliff Lodge
US/Mountain timezone

## T2K oscillation analysis results: latest analysis improvements at the far detector

Aug 5, 2022, 5:38 PM
22m
Ballroom 2

### Ballroom 2

Talk WG1: Neutrino Oscillation Physics

### Speaker

Kenji Yasutome (Kyoto University)

### Description

T2K is a long baseline neutrino experiment which exploits a neutrino and antineutrino beam produced at the Japan Particle Accelerator Research Centre (JPARC) to provide world-leading measurements of the parameters governing neutrino oscillation. Neutrino oscillations are measured by tuning the neutrino rates and spectra at a near detector complex, located at JPARC, and extrapolate them to the water-Cherenkov far detector, Super-Kamiokande, located 295 Km away, where oscillations are observed as modifications of such rates and spectra.

The latest T2K results include multiple analysis improvements, in particular a new sample is added at the far detector, requiring the presence of a pion in muon-neutrino interactions. It is the first time that a pion sample is included in the study of neutrino disappearance at T2K and, for the first time, a sample with more than one Cherenkov ring is exploited in the T2K oscillation analysis, opening the road for further samples with charged- and neutral-pion tagging. The inclusion of such sample enables proper control of the oscillated spectrum on a larger neutrino-energy range and on subleading neutrino-interaction processes. Finally, T2K is engaged with the Super-Kamiokande collaboration to combine T2K neutrino beam data and Super-Kamiokande atmospheric data to perform a joint fit to the oscillation parameters. Such combination allows the degeneracies between the measurement of the CP-violating phase $\delta_{CP}$ and the measurement of the ordering of the neutrino mass eigenstates to be lifted. Precise evaluation of the enhanced sensitivity of this joint fit will be presented.

Attendance type Virtual presentation

### Primary author

Kenji Yasutome (Kyoto University)