BNL E776: A Search for neutrino oscillations

We report on the results of BNL E776, carried out at the Brookhaven National Laboratory in the summer and fall of 1986. Its purpose was to search for neutrino oscillations, through the appearance of νe in a νμ beam. The experiment used a low energy narrow band beam of νμ with a mean energy of about 1.4 GeV, and a detector at a distance of 1 km from the target. With 3×1019 protons on target, no significant excess of electron neutrinos was detected. The 90% confidence limits obtained are Δm2≤0.11 eV2 in the limit of large mixing angle, and sin22θ≤0.018 in the limit of large Δm2.