Review of theta(13) and prospects for Double Chooz

The Double Chooz reactor neutrino experiment will be the next detector to search for a non vanishing theta(13) mixing angle with unprecedented sensitivity, which might open the way to unveiling CP violation in the leptonic sector. The measurement of this angle will be based on a precise comparison of the antineutrino spectrum at two identical detectors located at different distances from the Chooz nuclear reactor cores in France. Double Chooz is particularly attractive because of its capability to measure sin^2(2theta(13)) to 3 sigma significance if sin^2(2theta(13)) > 0.05 or to exclude sin^2(2theta(13)) down to 0.03 at 90% C.L. for Dm^2 = 2.5 x 10^(-3) eV^2 in three years of data taking with both detectors. The installation of the far detector started in May 2008 and the first neutrino results are expected in 2009. The advantages of reactor neutrino experiments to measure the theta(13) mixing angle are described in this article and in particular, the design, current status and expected performance of the Double Chooz detector.