Selected Publications
First exclusion of CP conservation in neutrino oscillation at 90% confidence level: The observation of muon to electron-neutrino oscillation opens the possibility of using neutrino oscillation to study CP violation by comparing neutrino flavour transformations between neutrinos and anti-neutrinos. CP violation has been observed in quarks but not yet measured in leptons (particles, including neutrinos, that do not undergo strong interactions). The size of quark CP violation is not enough to explain the matter anti-matter asymmetry of the universe, and as such, leptons' role may be significant. As reported in Physical Review Letters (2017) as an Editor's Suggestion, T2K performed a combined analysis of neutrino and anti-neutrino oscillations and notably excluded CP conservation at the 90% confidence level.
Combined Analysis of Neutrino and Antineutrino Oscillations at T2K
K. Abe et al., Phys. Rev. Lett., 11815 (2017)
Experimental observation of neutrino flavour transformation: As reported in Physical Review Letters (2014) as an Editor's Suggestion and since then cited almost 600 times, the T2K experiment for the first time experimentally observed neutrino flavour transformation. Muon neutrinos were produced at the J-PARC facility on Japan's east coast and sent 295 km through the ground to the Super-Kamiokande (SK) neutrino detector in western Japan. SK recorded a decreased number of muon neutrinos and the appearance of electron neutrinos, demonstrating flavour transformation. The discovery of an explicit oscillation confirms the neutrino oscillation mechanism (first observed with solar neutrinos) and opens the door to the use of neutrino oscillation as a probe of CP symmetry violation in leptons.
Observation of Electron Neutrino Appearance in a Muon Neutrino Beam
K. Abe et al. (T2K Collaboration), Phys. Rev. Lett., 11206 (2014)