2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/37032The KEK-to-Kamioka long-baseline neutrino experiment (K2K) has begun its investigation of neutrino oscillation, and has established the method of a long-baseline neutrino experiment. From the first 100 days of data-taking, a deficit of muon neutrino in the 1-GeV energy region after 250-km flight was observed at the 90% significance level.Proceedings of the XXXVIth Rencontres de Moriond EW, March 10-17, 2001, 8 pages, 17 eps-figures, uses moriondpp.styHigh Energy Physics - Experimenttext