arXiv subjects
Publications and source records attributed to Takanobu Ishii.
The disappearance of nu_mu was studied using the K2K-I dataset, which was taken before July, 2001. We observed indications of neutrino oscillation. The resultant oscillation-parameter region was consistent with the atmospheric neutrino result. The appearance of nu_e was searced for in the same dataset. No excess was found over the expected background.
During the first half of the K2K run, data corresponding to 4.8x10^19 POT were accumulated. In this data set, 56 accelerator-produced neutrino events were observed in the far detector, while the expected number from the near site measurements is 80.6+7.3-8.0. This means that the probability of the null- oscillation scenario is limited to less than 3%. A method for long-baseline neutrino experiments has been established.
The 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.