Results from the T2K Experiment on Neutrino Mixing Including a New Far Detector μ-like Sample

Area of Science:

• Particle Physics
• Neutrino Physics

Background:

• Neutrino oscillations provide insights into particle physics beyond the Standard Model.
• Understanding neutrino mixing parameters is crucial for particle physics research.

Purpose of the Study:

• To present improved measurements of three-flavor neutrino mixing.
• To constrain the charge-parity (CP) violating phase and neutrino mixing angles.

Main Methods:

• Utilized 19.7(16.3)×10^20 protons on target in neutrino and anti-neutrino enhanced beam modes.
• Incorporated new muon-neutrino, proton-tagged, and photon-tagged event samples.
• Improved flux and neutrino interaction modeling.

Main Results:

• Data favor the normal neutrino mass ordering.
• Preferred the upper octant for sin^2(θ23) with a near-maximal CP-violating phase.
• Best-fit values: δCP=-2.18+1.22-0.47, sin^2(θ23)=0.559+0.018-0.078, Δm32^2=(+2.506+0.039-0.052)×10^-3 eV^2.

Conclusions:

• T2K results strengthen evidence for normal mass ordering.
• Measurements provide precise constraints on neutrino oscillation parameters.