Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with $2.2\times10^{21}$ Protons on Target

• Published in: Physical review letters 2018, Vol.121 (17)
• Main Authors: Abe, K., Akutsu, R., Ali, A., Amey, J., Andreopoulos, C., Anthony, L., Antonova, M., Aoki, S., Ariga, A., Ashida, Y., Azuma, Y., Ban, S., Barbi, M., Barker, G.J., Barr, G., Barry, C., Batkiewicz, M., Bench, F., Berardi, V., Berkman, S., Berner, R.M., Berns, L., Bhadra, S., Bienstock, S., Blondel, A., Bolognesi, S., Bourguille, B., Boyd, S.B., Brailsford, D., Bravar, A., Bronner, C., Buizza Avanzini, M., Calcutt, J., Campbell, T., Cao, S., Cartwright, S.L., Catanesi, M.G., Cervera, A., Chappell, A., Checchia, C., Cherdack, D., Chikuma, N., Christodoulou, G., Coleman, J., Collazuol, G., Coplowe, D., Cudd, A., Dabrowska, A., de Rosa, G., Dealtry, T., Denner, P.F., Dennis, S.R., Densham, C., Di Lodovico, F., Dokania, N., Dolan, S., Drapier, O., Duffy, K.E., Dumarchez, J., Dunne, P., Emery-Schrenk, S., Ereditato, A., Fernandez, P., Feusels, T., Finch, A.J., Fiorentini, G.A., Fiorillo, G., Francois, C., Friend, M., Fujii, Y., Fujita, R., Fukuda, D., Fukuda, Y., Gameil, K., Giganti, C., Gizzarelli, F., Golan, T., Gonin, M., Hadley, D.R., Haegel, L., Haigh, J.T., Hamacher-Baumann, P., Hansen, D., Harada, J., Hartz, M., Hasegawa, T., Hastings, N.C., Hayashino, T., Hayato, Y., Hiramoto, A., Hogan, M., Holeczek, J., Hosomi, F., Ichikawa, A.K., Ikeda, M., Imber, J., Inoue, T., Intonti, R.A., Ishida, T., Ishii, T.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.121.171802

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×1020 protons on target in the neutrino (antineutrino) mode, 89 νe candidates and seven anti-νe candidates are observed, while 67.5 and 9.0 are expected for δCP=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δCP, does not include the CP-conserving cases (δCP=0, π). The best-fit values of other parameters are sin2θ23=0.526-0.036+0.032 and Δm322=2.463-0.070+0.071×10-3  eV2/c4.