Summary of the Reactor/ 13 Meeting At College de France, Paris April 22-23, 2003 Thierry Lasserre On Behalf the reactor/ 13 european working group CEA/Saclay Low energy Neutrino Workshop University of Alabama, Tuscaloosa May European momentum Working group: PCC & APC (from CHOOZ), CEA/Saclay MPI Heidelberg TU Munchen, Kurchatov Institute INFN/Bologna First meeting in December 2002 Second meeting in April 2003 Next around the end of the summer ? Goal: Is it possible to build a set of 2 detectors to measure/constrain 13 with a new reactor experiment before ? Where ? What the optimum detector design ? Preliminary answer should come this year T. Lasserre European momentum 22-23/04/03 Meeting : List of Participants H. de Kerret (PCC+APC) M. Obolinski (PCC+APC) O. Dadoun (PCC+APC) D. Vignaud (PCC+APC) J. Lamblin (PCC+APC) S. Schoenert (MPIK) T. Knoepfle (MPIK) L. Oberauer (TUM) F. Von Feilitzsch (TUM) C. Hagner (Virginia Polytechnic Institute) T. Schwetz (TUM) M. Selvi (INFN, Bologna) M. Cribier (Saclay+APC) C. Cavata (Saclay) T.L (Saclay) T. Lasserre Reactor/ 13 meeting, Paris, 22-23/04/03 Tuesday 22 April 14h 14h15 : Introduction 14h15 15h15 : Reactor Neutrino Experiments compared to Superbeams (Thomas Schwetz, TUM 45+15) 15h15 16h00 : The CHOOZ experiment & the |Ue3|2 measurement review of systematic errors. How and where to improve ? (H. de Kerret 30+15) 16h00 16h30 : Coffee break 16h30 17h30 : Review of the current proposals (Kr2Det, Kashiwasaki, etc ) Potential experiment sites in France ? (T. L 45+15) 17h30 18h00 : Discussion Wednesday 23 April 9h00 - 9h30 : Analysis methods to account for near and far detectors Systematic error handling (T. Schwetz, TUM, 30) 09h30 10h15 : Discussion Backgrounds: Accidental Correlated In-situ measurements (chaiperson: Stefan Schoenert) 10h15 10h45 : Coffee break 10h45 11h30 : Discussion - Detector design (chairperson: Lothar Oberauer) 11h30 12h30 : Conclusions Parameter degeneracy in LBL experiments LBL disappearance gives: sin 2 (2 23 ) 2 solutions : 23 & /2- 23 | m 2 13 | 2 solutions m 1 >m 3 or m 3 >m 1 LBL appearance probability given by: K 1,K 2,K 3 : known constants (within experimental error) dependence on sin(2 23 ), sin( 23 ) 2 solutions dependence on sign( m 2 31 ) 2 solutions -CP phase can run in [0,2 ] Interval of solutions in general P( e ) ~ K 1 sin 2 ( 23 ) sin 2 (2 13 ) + K 2 sin(2 23 ) sin( 13 ) sign( m 2 31 ) cos( ) K 3 sin(2 23 ) sin( 13 ) sin ( ) T. Lasserre |U e3 | 2 measurement with reactors Few MeV e disappearance experiments 1-P( e e ) = sin 2 (2 13 )sin 2 ( m 2 31 L/4E) + O( m 2 21 / m 2 31 ) Few MeV e + very short baseline No matter effect contribution (O(10 -4 ) relative effect) |U e3 | 2 measurement independent of sign( m 2 13 ) |U e3 | 2 measurement independent of the -CP phase sin 2 (2 13 ) P( e ) Achievable constraint on 13 with a reactor experiment (hep-ph/ , P. Huber et. al.) T. Schwetz Achievable constraint on 13 with a reactor experiment (hep-ph/ , P. Huber et. al.) T. Schwetz ~30-50 tons detectors Complementarity Reactor/Superbeam (hep-ph/ , P. Huber et. al.) Reactor experiment slightly less sensitive to non optimal m 2 31 LBL (JHF) rather sensitive to m 2 21 (especially if LMA-II) T. Schwetz Complementarity Reactor/Superbeam (hep-ph/ , P. Huber et. al.) Systematics Correlations & Degeneracies Reactor: dominated by systematics LBL: dominated by correlations and degeneracies T. Schwetz The past: CHOOZ (H.D.K) Site: CHOOZ reactor, Ardennes (France) 2 cores: 2x4200 MWth Depth: 300 mwe 5 tons of liquid scintillator (gadolinium loaded) ~ 1 km Exclusion e : m 2 sol < 7x10 -4 eV 2 (90% CL) (slightly lower limit obtained at Palo-Verde) Best constraint on sin 2 (2 13 ) < 0.14 Spectre des positrons e + p e + + n CHOOZ Systematics (H.D.K) T. Lasserre Systematics From Error originCHOOZ 2 non-identical detectors 2 identical detectors 2 id. detectors + low accidentals Remarks Reactor Complex cross section/fission1.9%--- Power0.7%--- E/Fission0.6%--- 2.1%