Abstract
We present measurements of disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One-hundred and twelve beam-originated neutrino events are observed in the fiducial volume of Super-Kamiokande with an expectation of events without oscillation. A distortion of the energy spectrum is also seen in 58 single-ring muonlike events with reconstructed energies. The probability that the observations are explained by the expectation for no neutrino oscillation is 0.0015% (). In a two-flavor oscillation scenario, the allowed region at is between 1.9 and at the 90% C.L. with a best-fit value of .
41 More- Received 17 June 2006
DOI:https://doi.org/10.1103/PhysRevD.74.072003
©2006 American Physical Society