The First Results of K2K long-baseline Neutrino Oscillation Experiment

TL;DR

The K2K experiment's initial findings suggest neutrino oscillations by comparing observed events with expected counts, marking a significant step in long-baseline neutrino research.

Contribution

This paper reports the first results of the K2K long-baseline neutrino oscillation experiment, providing initial data and analysis of neutrino interactions over a 250 km distance.

Findings

Observed 3 events versus expected 12.3 without oscillations.

Initial data supports the existence of neutrino oscillations.

Detailed measurements of neutrino interactions at KEK are underway.

Abstract

The first results of the K2K(KEK to Kamioka) long-baseline neutrino oscillation experiment are presented in this talk. In 1999 7.2x10^18 protons on target were delivered to the experiment. During this period of running there were 3 events fully contained in the Super-Kamiokande inner detector fiducial area which occurred during the beam spill timing window. In the case of no oscillations the expected number of events during this period was 12.3+1.7-1.9. The near detectors located at KEK also have begun detailed measurements of neutrino interactions in water at around 1 GeV.