HEP Seminar

by Daniel Barrow (Oxford University)

Tuesday 7 Apr 2026, 12:00 → 13:30 Europe/London

2nd Floor Meeting Room (Liverpool Physics)

Precision measurements of neutrino oscillations are central to resolving key open questions in particle physics, including the neutrino mass ordering and the existence of CP violation in the lepton sector. Accelerator-based experiments probe these parameters using neutrino beams over fixed baselines, while atmospheric neutrino experiments observe neutrinos that traverse distances from tens to thousands of kilometres before detection. The differing baselines and energy spectra of these sources provide complementary sensitivity to oscillation parameters, including the mass ordering, the octant of mixing angle θ23, and the CP-violating phase δCP.

In this talk, I present the first joint oscillation analysis combining accelerator data from the Tokai-to-Kamiokande experiment with atmospheric neutrino samples observed in Super-Kamiokande (Phys. Rev. Lett. 134, 011801). The analysis employs a common neutrino interaction model and consistently treats detector systematic uncertainties arising from the use of a shared detector. The combined fit yields improved constraints on oscillation parameters, including a ∼1.9σ exclusion of CP conservation and enhanced sensitivity to the neutrino mass ordering. These results illustrate the enhanced physics reach achievable through joint analyses. Prospects for further improvements and extensions to next-generation experiments will also be discussed.