Search for the \theta_{13} Neutrino Mixing Angle Using Reactor Anti-Neutrinos

Abstract

The measurement of the last undetermined neutrino mixing angle \theta_{13} is the main goal of the future experimental research on neutrino oscillations. At present, \theta_{13} is only known to be much smaller than the two other mixing angles, \theta_{12} and \theta_{23}. The present bound, which is dominated by the result of the CHOOZ reactor experiment, is \sin^{2}2\theta_{13}<0.08 (at 90 % confidence level). However, it is widely recognized that the potential of reactor anti-neutrino disappearance experiments has not been fully exploited yet. A rich experimental program is underway, which aims at exploring in the near future up to \sin^{2}2\theta_{13}\lesssim0.01. The targeted sensitivity requires a clear-cut strategy to reduce significantly both statistical and systematical errors with respect to past reactor experiments. A key feature for the success of all projects is the installation of one or more near identical detectors. The experimental concept and the status of the upcoming or proposed reactor experiments, and as well the prospects of the reactor-based search for \theta_{13} are reviewed.