Speaker
Description
T2K (Tokai to Kamioka) is a Japan based long-baseline neutrino oscillation experiment designed to measure (anti-)neutrino flavor oscillations. A neutrino beam peaked around 0.6 GeV is produced in Tokai and directed toward the water Cherenkov detector Super-Kamiokande, which is located 295 km away. A complex of near detectors is located at 280 m and is used to constrain the flux and cross-section uncertainties by measuring the neutrinos before oscillations. In 2014, T2K started a campaign to measure the phase $\delta_{CP}$, an unknown element of the Pontecorvo-Maki-Nakagata-Sakata matrix, that can provide a test of the violation or conservation of the CP symmetry in the neutrino sector. To achieve this goal, T2K is taking data with a neutrino and antineutrino enhanced beam investigating asymmetries in the electron neutrino and antineutrino appearance probabilities. The most recent result obtained combining data taken with a neutrino and antineutrino beam showed that the CP-conserving cases are excluded at 90% confidence level. In this presentation the methodology employed to reach this result is outlined with particular emphasis on the measurement of the flux and cross-section uncertainties at the T2K near detector. One of the largest systematic uncertainties in T2K oscillation analysis comes from present limited knowledge of (anti-)neutrino-nucleus cross-sections. Neutrino scattering understanding is crucial for the interpretation of neutrino oscillation and details on how is treated and its impact on T2K oscillation analysis are discussed in this presentation.
| Collaboration name | T2K |
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