Limits on Neutrino Oscillations from the CHOOZ Experiment

TL;DR

The CHOOZ experiment's comprehensive data analysis sets new upper limits on neutrino oscillation parameters, finding no evidence for anti_nue disappearance within the tested parameter space at 90% confidence.

Contribution

This study provides the most stringent constraints to date on neutrino oscillation parameters from the CHOOZ experiment, including new bounds on Delta m^2 and sin^2(2 theta).

Findings

No evidence for neutrino oscillations at 90% confidence.

Established upper limits on Delta m^2 and sin^2(2 theta).

Results are independent of absolute flux normalization.

Abstract

We present new results based on the entire CHOOZ data sample. We find (at 90% confidence level) no evidence for neutrino oscillations in the anti_nue disappearance mode, for the parameter region given by approximately Delta m**2 > 7 x 10**-4 eV^2 for maximum mixing, and sin**2(2 theta) = 0.10 for large Delta m**2. Lower sensitivity results, based only on the comparison of the positron spectra from the two different-distance nuclear reactors, are also presented; these are independent of the absolute normalization of the anti_nue flux, the cross section, the number of target protons and the detector efficiencies.