The atmospheric neutrino background for proton decay via p→e+π0 in ring imaging water Cherenkov detectors is studied with an artificial accelerator neutrino beam for the first time. In total, 3.14×105 neutrino events corresponding to about 10 megaton-years of atmospheric neutrino interactions were collected by a 1000 ton water Cherenkov detector (KT). The KT charged-current single π0 production data are well reproduced by simulation programs of neutrino and secondary hadronic interactions used in the Super-Kamiokande (SK) proton decay search. The obtained p→e+π0 background rate by the KT data for SK from the atmospheric neutrinos whose energies are below 3 GeV is 1.63-0.33+0.42(stat)-0.51+0.45(syst)(megaton-year)- 1. This result is also relevant to possible future, megaton-scale water Cherenkov detectors. © 2008 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review D - Particles, Fields, Gravitation and Cosmology
Mine, S., Alcaraz, J., Andringa, S., Aoki, S., Argyriades, J., Asakura, K., Ashie, R., Berghaus, F., Berns, H., Bhang, H., Blondel, A., Borghi, S., Bouchez, J., Burguet-Castell, J., Casper, D., Catala, J., Cavata, C., Cervera, A., Chen, S., Cho, K., Choi, J., Dore, U., Espinal, X., Fechner, M., Fernandez, E., Fujii, Y., Fukuda, Y., & Gomez-Cadenas, J. (2008). Experimental study of the atmospheric neutrino backgrounds for p→e+π0 searches in water Cherenkov detectors. Physical Review D - Particles, Fields, Gravitation and Cosmology, 77 (3) https://doi.org/10.1103/PhysRevD.77.032003