Search for neutrino oscillations at the Palo Verde nuclear reactors

We report on the initial results from a measurement of the antineutrino 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 antineutrino flux agrees with that predicted in the absence of oscillations excluding at 90% C.L. ¯ ne -¯ nx oscillations with Dm 2 . 1.12 3 10 23 eV 2 for maximal mixing and sin 2 2 u. 0.21 for large Dm 2 . Our results support the conclusion that the