a Search for the Oscillation of Muon Neutrinos to Electron Neutrinos.

A search was done at Brookhaven National Laboratory for the oscillation of muon neutrinos to electron neutrinos. The neutrino beam energy was centered at 1.2 GeV with a 15% spread; and the 250 ton aluminum and concrete detector is located 1 kilometer from the source. Approximately 3 times 10^{19 } protons were accumulated on target yielding 7100 muon neutrino events after correcting for acceptance. The muon neutrino event rate and the measured energy spectrum are in reasonable agreement with Monte Carlo calculations, but there are indications of an excess of electron neutrinos over the number expected.