The Double Chooz experiment: A search for the mixing angle θ₁₃

Double Chooz is an experiment to search for the electron neutrino component of the third neutrino mass eigenstate (i.e., a non-vanishing θ₁₃ mixing angle) by measuring reactor antineutrino disappearance over a 1 km baseline. It will be the first of a new generation of neutrino experiments using identical detectors at different distances from the neutrino source to reduce the systematic errors due to the uncertainties on the neutrino flux and on the detector efficiency. The experiment is designed to measure the sin² 2θ₁₃ quantity or improve the current best limit by almost an order of magnitude. Its potential is a measurement at 3ρ if sin² 2θ₁₃ ≥ 0.05 or an exclusion down to 0.03 at 90% C.L. for Δm₃₁² = 2.5 × 10^-3 eV².