Résumé du preprint DAPNIA-04-84

DAPNIA-04-84
Letter of Intent for Double-CHOOZ: a Search for the Mixing Angle Theta13
F.Ardellier, I.Barabanov, J.C.Barriere, M.Bauer, L.Bezrukov, C.Buck, C.Cattadori, B.Courty, M.Cribier, F.Dalnoki-Veress, N.Danilov, H.de Kerret, A.Di Vacri, A.Etenko, M.Fallot, Ch.Grieb, M.Goeger, A.Guertin, T.Kirchner, Y.S.Krylov, D.Kryn, C.Hagner, W.Hampel, F.X.Hartmann, P.Huber, J.Jochum, T.Lachenmaier, Th.Lasserre, Ch.Lendvai, M.Lindner, F.Marie, J.Martino, G.Mention, A.Milsztajn, J.P.Meyer, D.Motta, L.Oberauer, M.Obolensky, L.Pandola, W.Potzel, S.Schoenert, U.Schwan, T.Schwetz, S.Scholl, L.Scola, M.Skorokhvatov, S.Sukhotin, A.Letourneau, D.Vignaud, F.von Feilitzsch, W.Winter, E.Yanovich
Tremendous progress has been achieved in neutrino oscillation physics during the last few years. However, the smallness of the $\\t13$ neutrino mixing angle still remains enigmatic. The current best constraint comes from the CHOOZ reactor neutrino experiment $\\s2t13 < 0.2$ (at 90% C.L., for $\\adm2=2.0 10^{-3} \\text{eV}^2$). We propose a new experiment on the same site, Double-CHOOZ, to explore the range of $\\s2t13$ from 0.2 to 0.03, within three years of data taking. The improvement of the CHOOZ result requires an increase in the statistics, a reduction of the systematic error below one percent, and a careful control of the cosmic ray induced background. Therefore, Double-CHOOZ will use two identical detectors, one at $\\sim$150 m and another at 1.05 km distance from the nuclear cores. The plan is to start data taking with two detectors in 2008, and to reach a sensitivity of 0.05 in 2009, and 0.03 in 2011.