Search for Neutrino Oscillations at the Palo Verde Nuclear Reactors

TL;DR

This study measures anti-neutrino flux at 800m from Palo Verde reactors to investigate neutrino oscillations, finding results consistent with no oscillations within certain parameter bounds.

Contribution

First measurement of anti-neutrino flux at this site using a gadolinium scintillator, setting new limits on neutrino oscillation parameters.

Findings

Anti-neutrino flux matches predictions within 5%.

Excluded certain oscillation parameters at 90% confidence level.

Provided constraints on $ mar u_e - ar u_x$ oscillations.

Abstract

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 to better than 5%, excluding at 90% CL $\rm\bar\nu_e - \bar\nu_x$ oscillations with $\Delta m^2 > 1.12\times 10^{-3}$ eV^2 for maximal mixing and $\sin^2{2\theta} > 0.21$ for large $\Delta m^2$.