Combining long-baseline neutrino measurements: Recent results from NOvA and T2K

The two current-generation long-baseline experiments NOvA and T2K measure oscillations over 810 km and 295 km baselines respectively. Measuring neutrino mixing over different baselines can provide sensitivity to different parts of the three-flavor PMNS mixing model by enhancing or suppressing matter effects. Each experiment prefers compatible but different best-fit parameter values so a joint fit can leverage this to break some of the degeneracy in the parameter space.

Each of the collaborations' models and analyses have been tailored to best increase the sensitivity of their experiment. A unified framework has been developed which integrates the analysis of each experiment, maintaining their distinct philosophies, while allowing for a statistically robust exploration of the full joint likelihood.

T2K has also developed a combined analysis of beam and atmospheric neutrino data with the Super-Kamiokande collaboration. While the baseline of accelerator experiments can be tuned to specific distances and beam energies, atmospheric neutrinos have a wide range of baselines and energies.

These joint results demonstrate the immense value in cross-experiment collaboration, not only in terms of the sensitivity to physics, but also a deeper understanding of each other's work.