Search for Neutrino Oscillations at the Palo Verde Nuclear Reactors

We report on the initial results from a measurement of the anti-neutrino flux and spectrum at a distance of about 800 m from the three reactors of the Palo Verde Nuclear Generating Station using a segmented gadolinium-loaded scintillation detector. We find that the anti-neutrino flux agrees with that predicted in the absence of oscillations excluding at 90% CL ¯ ν e − ¯ ν x oscillations with ∆ m 2 > 1 . 12 × 10 − 3 eV 2 for maximal mixing and sin 2 2 θ > 0 . 21 for large ∆ m 2 .