Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at \sqrt{s_{\rm{NN}}} = 200 GeV: Jet-quenching and the response of partonic matter

Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at = 200 GeV: Jet-quenching and the response of partonic matter

A. Adare University of Colorado, Boulder, CO 80309, U.S.    S. Afanasiev Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    C. Aidala Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    N.N. Ajitanand Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    Y. Akiba RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    H. Al-Bataineh New Mexico State University, Las Cruces, NM 88003, U.S.    J. Alexander Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    A. Al-Jamel New Mexico State University, Las Cruces, NM 88003, U.S.    K. Aoki Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    L. Aphecetche SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes) BP 20722 - 44307, Nantes, France    R. Armendariz New Mexico State University, Las Cruces, NM 88003, U.S.    S.H. Aronson Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J. Asai RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    E.T. Atomssa Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    R. Averbeck Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    T.C. Awes Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    B. Azmoun Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    V. Babintsev IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    G. Baksay Florida Institute of Technology, Melbourne, FL 32901, U.S.    L. Baksay Florida Institute of Technology, Melbourne, FL 32901, U.S.    A. Baldisseri Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    K.N. Barish University of California - Riverside, Riverside, CA 92521, U.S.    P.D. Barnes Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    B. Bassalleck University of New Mexico, Albuquerque, NM 87131, U.S.    S. Bathe University of California - Riverside, Riverside, CA 92521, U.S.    S. Batsouli Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S. Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    V. Baublis PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    F. Bauer University of California - Riverside, Riverside, CA 92521, U.S.    A. Bazilevsky Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    S. Belikov Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. Iowa State University, Ames, IA 50011, U.S.    R. Bennett Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    Y. Berdnikov Saint Petersburg State Polytechnic University, St. Petersburg, Russia    A.A. Bickley University of Colorado, Boulder, CO 80309, U.S.    M.T. Bjorndal Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    J.G. Boissevain Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    H. Borel Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    K. Boyle Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    M.L. Brooks Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    D.S. Brown New Mexico State University, Las Cruces, NM 88003, U.S.    D. Bucher Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    H. Buesching Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    V. Bumazhnov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    G. Bunce Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J.M. Burward-Hoy Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    S. Butsyk Los Alamos National Laboratory, Los Alamos, NM 87545, U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    S. Campbell Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    J.-S. Chai KAERI, Cyclotron Application Laboratory, Seoul, South Korea    B.S. Chang Yonsei University, IPAP, Seoul 120-749, Korea    J.-L. Charvet Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    S. Chernichenko IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    J. Chiba KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    C.Y. Chi Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    M. Chiu Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S. University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.    I.J. Choi Yonsei University, IPAP, Seoul 120-749, Korea    T. Chujo Vanderbilt University, Nashville, TN 37235, U.S.    P. Chung Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    A. Churyn IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    V. Cianciolo Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    C.R. Cleven Georgia State University, Atlanta, GA 30303, U.S.    Y. Cobigo Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    B.A. Cole Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    M.P. Comets IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    P. Constantin Iowa State University, Ames, IA 50011, U.S. Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    M. Csanád ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary    T. Csörgő KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, Hungary    T. Dahms Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    K. Das Florida State University, Tallahassee, FL 32306, U.S.    G. David Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M.B. Deaton Abilene Christian University, Abilene, TX 79699, U.S.    K. Dehmelt Florida Institute of Technology, Melbourne, FL 32901, U.S.    H. Delagrange SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes) BP 20722 - 44307, Nantes, France    A. Denisov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    D. d’Enterria Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    A. Deshpande RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    E.J. Desmond Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    O. Dietzsch Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    A. Dion Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    M. Donadelli Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    J.L. Drachenberg Abilene Christian University, Abilene, TX 79699, U.S.    O. Drapier Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    A. Drees Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    A.K. Dubey Weizmann Institute, Rehovot 76100, Israel    A. Durum IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    V. Dzhordzhadze University of California - Riverside, Riverside, CA 92521, U.S. University of Tennessee, Knoxville, TN 37996, U.S.    Y.V. Efremenko Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    J. Egdemir Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    F. Ellinghaus University of Colorado, Boulder, CO 80309, U.S.    W.S. Emam University of California - Riverside, Riverside, CA 92521, U.S.    A. Enokizono Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    H. En’yo RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    B. Espagnon IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    S. Esumi Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K.O. Eyser University of California - Riverside, Riverside, CA 92521, U.S.    D.E. Fields University of New Mexico, Albuquerque, NM 87131, U.S. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M. Finger Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    F. Fleuret Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    S.L. Fokin Russian Research Center “Kurchatov Institute”, Moscow, Russia    B. Forestier LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France    Z. Fraenkel Weizmann Institute, Rehovot 76100, Israel    J.E. Frantz Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    A. Franz Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A.D. Frawley Florida State University, Tallahassee, FL 32306, U.S.    K. Fujiwara RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    Y. Fukao Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S.-Y. Fung University of California - Riverside, Riverside, CA 92521, U.S.    T. Fusayasu Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan    S. Gadrat LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France    I. Garishvili University of Tennessee, Knoxville, TN 37996, U.S.    F. Gastineau SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes) BP 20722 - 44307, Nantes, France    M. Germain SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes) BP 20722 - 44307, Nantes, France    A. Glenn University of Colorado, Boulder, CO 80309, U.S. University of Tennessee, Knoxville, TN 37996, U.S.    H. Gong Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    M. Gonin Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    J. Gosset Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    Y. Goto RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    R. Granier de Cassagnac Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    N. Grau Iowa State University, Ames, IA 50011, U.S.    S.V. Greene Vanderbilt University, Nashville, TN 37235, U.S.    M. Grosse Perdekamp University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    T. Gunji Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    H.-Å. Gustafsson Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    T. Hachiya Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    A. Hadj Henni SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes) BP 20722 - 44307, Nantes, France    C. Haegemann University of New Mexico, Albuquerque, NM 87131, U.S.    J.S. Haggerty Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M.N. Hagiwara Abilene Christian University, Abilene, TX 79699, U.S.    H. Hamagaki Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    R. Han Peking University, Beijing, People’s Republic of China    H. Harada Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    E.P. Hartouni Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    K. Haruna Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    M. Harvey Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    E. Haslum Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    K. Hasuko RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    R. Hayano Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    M. Heffner Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    T.K. Hemmick Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    T. Hester University of California - Riverside, Riverside, CA 92521, U.S.    J.M. Heuser RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    X. He Georgia State University, Atlanta, GA 30303, U.S.    H. Hiejima University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.    J.C. Hill Iowa State University, Ames, IA 50011, U.S.    R. Hobbs University of New Mexico, Albuquerque, NM 87131, U.S.    M. Hohlmann Florida Institute of Technology, Melbourne, FL 32901, U.S.    M. Holmes Vanderbilt University, Nashville, TN 37235, U.S.    W. Holzmann Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    K. Homma Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    B. Hong Korea University, Seoul, 136-701, Korea    T. Horaguchi RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    D. Hornback University of Tennessee, Knoxville, TN 37996, U.S.    M.G. Hur KAERI, Cyclotron Application Laboratory, Seoul, South Korea    T. Ichihara RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    K. Imai Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    M. Inaba Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y. Inoue Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    D. Isenhower Abilene Christian University, Abilene, TX 79699, U.S.    L. Isenhower Abilene Christian University, Abilene, TX 79699, U.S.    M. Ishihara RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    T. Isobe Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    M. Issah Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    A. Isupov Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    B.V. Jacak jacak@skipper.physics.sunysb.edu Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    J. Jia Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    J. Jin Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    O. Jinnouchi RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    B.M. Johnson Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    K.S. Joo Myongji University, Yongin, Kyonggido 449-728, Korea    D. Jouan IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    F. Kajihara Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S. Kametani Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan Waseda University, Advanced Research Institute for Science and Engineering, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan    N. Kamihara RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    J. Kamin Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    M. Kaneta RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J.H. Kang Yonsei University, IPAP, Seoul 120-749, Korea    H. Kanou RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    T. Kawagishi Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    D. Kawall RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A.V. Kazantsev Russian Research Center “Kurchatov Institute”, Moscow, Russia    S. Kelly University of Colorado, Boulder, CO 80309, U.S.    A. Khanzadeev PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    J. Kikuchi Waseda University, Advanced Research Institute for Science and Engineering, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan    D.H. Kim Myongji University, Yongin, Kyonggido 449-728, Korea    D.J. Kim Yonsei University, IPAP, Seoul 120-749, Korea    E. Kim System Electronics Laboratory, Seoul National University, Seoul, South Korea    Y.-S. Kim KAERI, Cyclotron Application Laboratory, Seoul, South Korea    E. Kinney University of Colorado, Boulder, CO 80309, U.S.    A. Kiss ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary    E. Kistenev Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A. Kiyomichi RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    J. Klay Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    C. Klein-Boesing Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    L. Kochenda PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    V. Kochetkov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    B. Komkov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    M. Konno Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    D. Kotchetkov University of California - Riverside, Riverside, CA 92521, U.S.    A. Kozlov Weizmann Institute, Rehovot 76100, Israel    A. Král Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    A. Kravitz Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    P.J. Kroon Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J. Kubart Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    G.J. Kunde Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    N. Kurihara Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    K. Kurita Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    M.J. Kweon Korea University, Seoul, 136-701, Korea    Y. Kwon University of Tennessee, Knoxville, TN 37996, U.S. Yonsei University, IPAP, Seoul 120-749, Korea    G.S. Kyle New Mexico State University, Las Cruces, NM 88003, U.S.    R. Lacey Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    Y.-S. Lai Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    J.G. Lajoie Iowa State University, Ames, IA 50011, U.S.    A. Lebedev Iowa State University, Ames, IA 50011, U.S.    Y. Le Bornec IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    S. Leckey Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    D.M. Lee Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    M.K. Lee Yonsei University, IPAP, Seoul 120-749, Korea    T. Lee System Electronics Laboratory, Seoul National University, Seoul, South Korea    M.J. Leitch Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    M.A.L. Leite Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    B. Lenzi Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    H. Lim System Electronics Laboratory, Seoul National University, Seoul, South Korea    T. Liška Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    A. Litvinenko Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    M.X. Liu Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    X. Li China Institute of Atomic Energy (CIAE), Beijing, People’s Republic of China    X.H. Li University of California - Riverside, Riverside, CA 92521, U.S.    B. Love Vanderbilt University, Nashville, TN 37235, U.S.    D. Lynch Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    C.F. Maguire Vanderbilt University, Nashville, TN 37235, U.S.    Y.I. Makdisi Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A. Malakhov Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    M.D. Malik University of New Mexico, Albuquerque, NM 87131, U.S.    V.I. Manko Russian Research Center “Kurchatov Institute”, Moscow, Russia    Y. Mao Peking University, Beijing, People’s Republic of China RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    L. Mašek Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    H. Masui Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    F. Matathias Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    M.C. McCain University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.    M. McCumber Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    P.L. McGaughey Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    Y. Miake Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    P. Mikeš Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    K. Miki Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    T.E. Miller Vanderbilt University, Nashville, TN 37235, U.S.    A. Milov Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    S. Mioduszewski Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    G.C. Mishra Georgia State University, Atlanta, GA 30303, U.S.    M. Mishra Department of Physics, Banaras Hindu University, Varanasi 221005, India    J.T. Mitchell Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M. Mitrovski Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    A. Morreale University of California - Riverside, Riverside, CA 92521, U.S.    D.P. Morrison Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J.M. Moss Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    T.V. Moukhanova Russian Research Center “Kurchatov Institute”, Moscow, Russia    D. Mukhopadhyay Vanderbilt University, Nashville, TN 37235, U.S.    J. Murata Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S. Nagamiya KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    Y. Nagata Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    J.L. Nagle University of Colorado, Boulder, CO 80309, U.S.    M. Naglis Weizmann Institute, Rehovot 76100, Israel    I. Nakagawa RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    Y. Nakamiya Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    T. Nakamura Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    K. Nakano RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    J. Newby Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    M. Nguyen Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    B.E. Norman Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    A.S. Nyanin Russian Research Center “Kurchatov Institute”, Moscow, Russia    J. Nystrand Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    E. O’Brien Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    S.X. Oda Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    C.A. Ogilvie Iowa State University, Ames, IA 50011, U.S.    H. Ohnishi RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    I.D. Ojha Vanderbilt University, Nashville, TN 37235, U.S.    H. Okada Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    K. Okada RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M. Oka Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    O.O. Omiwade Abilene Christian University, Abilene, TX 79699, U.S.    A. Oskarsson Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    I. Otterlund Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    M. Ouchida Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    K. Ozawa Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    R. Pak Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    D. Pal Vanderbilt University, Nashville, TN 37235, U.S.    A.P.T. Palounek Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    V. Pantuev Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    V. Papavassiliou New Mexico State University, Las Cruces, NM 88003, U.S.    J. Park System Electronics Laboratory, Seoul National University, Seoul, South Korea    W.J. Park Korea University, Seoul, 136-701, Korea    S.F. Pate New Mexico State University, Las Cruces, NM 88003, U.S.    H. Pei Iowa State University, Ames, IA 50011, U.S.    J.-C. Peng University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.    H. Pereira Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    V. Peresedov Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    D.Yu. Peressounko Russian Research Center “Kurchatov Institute”, Moscow, Russia    C. Pinkenburg Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    R.P. Pisani Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M.L. Purschke Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A.K. Purwar Los Alamos National Laboratory, Los Alamos, NM 87545, U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    H. Qu Georgia State University, Atlanta, GA 30303, U.S.    J. Rak Iowa State University, Ames, IA 50011, U.S. University of New Mexico, Albuquerque, NM 87131, U.S.    A. Rakotozafindrabe Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    I. Ravinovich Weizmann Institute, Rehovot 76100, Israel    K.F. Read Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S. University of Tennessee, Knoxville, TN 37996, U.S.    S. Rembeczki Florida Institute of Technology, Melbourne, FL 32901, U.S.    M. Reuter Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    K. Reygers Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    V. Riabov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    Y. Riabov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    G. Roche LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France    A. Romana Deceased Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    M. Rosati Iowa State University, Ames, IA 50011, U.S.    S.S.E. Rosendahl Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    P. Rosnet LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France    P. Rukoyatkin Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    V.L. Rykov RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S.S. Ryu Yonsei University, IPAP, Seoul 120-749, Korea    B. Sahlmueller Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    N. Saito Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    T. Sakaguchi Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan Waseda University, Advanced Research Institute for Science and Engineering, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan    S. Sakai Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    H. Sakata Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    V. Samsonov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    H.D. Sato Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S. Sato Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    S. Sawada KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    J. Seele University of Colorado, Boulder, CO 80309, U.S.    R. Seidl University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.    V. Semenov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    R. Seto University of California - Riverside, Riverside, CA 92521, U.S.    D. Sharma Weizmann Institute, Rehovot 76100, Israel    T.K. Shea Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    I. Shein IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    A. Shevel PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    T.-A. Shibata RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    K. Shigaki Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    M. Shimomura Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    T. Shohjoh Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K. Shoji Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    A. Sickles Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    C.L. Silva Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    D. Silvermyr Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    C. Silvestre Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    K.S. Sim Korea University, Seoul, 136-701, Korea    C.P. Singh Department of Physics, Banaras Hindu University, Varanasi 221005, India    V. Singh Department of Physics, Banaras Hindu University, Varanasi 221005, India    S. Skutnik Iowa State University, Ames, IA 50011, U.S.    M. Slunečka Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia    W.C. Smith Abilene Christian University, Abilene, TX 79699, U.S.    A. Soldatov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    R.A. Soltz Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S.    W.E. Sondheim Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    S.P. Sorensen University of Tennessee, Knoxville, TN 37996, U.S.    I.V. Sourikova Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    F. Staley Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    P.W. Stankus Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    E. Stenlund Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    M. Stepanov New Mexico State University, Las Cruces, NM 88003, U.S.    A. Ster KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, Hungary    S.P. Stoll Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    T. Sugitate Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    C. Suire IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    J.P. Sullivan Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    J. Sziklai KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, Hungary    T. Tabaru RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    S. Takagi Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    E.M. Takagui Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    A. Taketani RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    K.H. Tanaka KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    Y. Tanaka Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan    K. Tanida RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M.J. Tannenbaum Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    A. Taranenko Chemistry Department, Stony Brook University, Stony Brook, SUNY, NY 11794-3400, U.S.    P. Tarján Debrecen University, H-4010 Debrecen, Egyetem tér 1, Hungary    T.L. Thomas University of New Mexico, Albuquerque, NM 87131, U.S.    M. Togawa Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    A. Toia Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    J. Tojo RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    L. Tomášek Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    H. Torii RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    R.S. Towell Abilene Christian University, Abilene, TX 79699, U.S.    V-N. Tram Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    I. Tserruya Weizmann Institute, Rehovot 76100, Israel    Y. Tsuchimoto Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    S.K. Tuli Department of Physics, Banaras Hindu University, Varanasi 221005, India    H. Tydesjö Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    N. Tyurin IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    C. Vale Iowa State University, Ames, IA 50011, U.S.    H. Valle Vanderbilt University, Nashville, TN 37235, U.S.    H.W. van Hecke Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.    J. Velkovska Vanderbilt University, Nashville, TN 37235, U.S.    R. Vertesi Debrecen University, H-4010 Debrecen, Egyetem tér 1, Hungary    A.A. Vinogradov Russian Research Center “Kurchatov Institute”, Moscow, Russia    M. Virius Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    V. Vrba Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    E. Vznuzdaev PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    M. Wagner Kyoto University, Kyoto 606-8502, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan    D. Walker Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S.    X.R. Wang New Mexico State University, Las Cruces, NM 88003, U.S.    Y. Watanabe RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    J. Wessels Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    S.N. White Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    N. Willis IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    D. Winter Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    C.L. Woody Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    M. Wysocki University of Colorado, Boulder, CO 80309, U.S.    W. Xie University of California - Riverside, Riverside, CA 92521, U.S. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    Y. Yamaguchi Waseda University, Advanced Research Institute for Science and Engineering, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan    A. Yanovich IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    Z. Yasin University of California - Riverside, Riverside, CA 92521, U.S.    J. Ying Georgia State University, Atlanta, GA 30303, U.S.    S. Yokkaichi RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.    G.R. Young Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    I. Younus University of New Mexico, Albuquerque, NM 87131, U.S.    I.E. Yushmanov Russian Research Center “Kurchatov Institute”, Moscow, Russia    W.A. Zajc Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S.    O. Zaudtke Institut für Kernphysik, University of Muenster, D-48149 Muenster, Germany    C. Zhang Columbia University, New York, NY 10027 and Nevis Laboratories, Irvington, NY 10533, U.S. Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.    S. Zhou China Institute of Atomic Energy (CIAE), Beijing, People’s Republic of China    J. Zimányi Deceased KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, Hungary    L. Zolin Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia
September 23, 2019
Abstract

Azimuthal angle () correlations are presented for charged hadrons from dijets for  GeV/ in Au+Au collisions at = 200 GeV. With increasing , the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to data suggest that the away-side can be divided into a partially suppressed “head” region centered at , and an enhanced “shoulder” region centered at . The spectrum for the “head” region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the “shoulder” region is independent of centrality and trigger , which offers constraints on energy transport mechanisms and suggests that the “shoulder” region contains the medium response to energetic jets.

pacs:
25.75.Dw

PHENIX Collaboration

High transverse momentum () partons are valuable probes of the high energy density matter created at the Relativistic Heavy-Ion Collider (RHIC). These partons lose a large fraction of their energy in the matter prior to forming hadrons, a phenomenon known as jet-quenching. Such energy loss is predicted to lead to strong suppression of both single- and correlated away-side dihadron yields at high  Gyulassy:2003mc , consistent with experimental findings Adler:2003au ; Adler:2002tq . The exact mechanism for energy loss is not yet understood. Recent results of dihadron azimuthal angle () correlations have indicated strong modification of the away-side jet Adams:2005ph ; Adler:2005ee ; Adler:2002tq ; Adare:2006nr . For high hadron pairs, such modification is manifested by a partially suppressed away-side peak at  Adler:2002tq . This has been interpreted as evidence for the fragmentation of jets that survive their passage through the medium.

For intermediate charged hadron pairs, the away-side jet was observed to peak at  Adler:2005ee ; Adare:2006nr , suggesting that the energy lost by high partons is transported to lower hadrons at angles away from . The proposed mechanisms for such energy transport include medium deflection of hard Chiu:2006pu or shower partons Armesto:2004pt ,large-angle gluon radiation Vitev:2005yg ; Polosa:2006hb , Cherenkov gluon radiation Koch:2005sx , and “Mach Shock” medium excitations Casalderrey-Solana:2004qm .

In this letter we present a detailed “mapping” of the and centrality dependence of away-side jet shapes and yields. These measurements (1) allow a detailed investigation of the jet distributions centered around and , (2) provide new insight on the interplay between jet quenching and the response of the medium to the lost energy, and (3) provide new constraints for distinguishing the competing mechanisms for energy transport.

The results presented here are based on minimum-bias (MB) Au+Au and p+p datasets as well as a “photon” level-1 triggered (PT) p+p dataset Adare:2006hc collected with the PHENIX detector Adcox:2003zm at =200 GeV, during the 2004-2005 RHIC running periods. The collision vertex was required to be within  30cm of the nominal crossing point. The event centrality was determined via the method in Ref. Adcox:2003zm . A total of 840 million Au+Au events were analyzed. Charged particles were reconstructed in the two central arms of PHENIX, each covering -0.35 to 0.35 in pseudo-rapidity and in azimuth. The tracking system consists of the drift chambers and two layers of multi-wire proportional chambers with pad readout (PC1 and PC3), achieving a momentum resolution of  (GeV/Adler:2003au .

Dihadron azimuthal angle correlations are obtained by correlating “trigger” (type ) hadrons with “partner” (type ) hadrons. The MB and PT p+p datasets are used for trigger GeV/ and GeV/, respectively. To reduce background from decays and conversions, tracks are required to have a matching hit within a window in PC3. For GeV/, additional matching hit at the electromagnetic calorimeter (EMC) was required to suppress background tracks that randomly associate with the PC3 Adler:2003au . For triggers with GeV/, a dependent energy cut in the EMC and a tight matching cut at the PC3 were applied to reduce the background to Adler:2005ad . This energy cut greatly reduces PT trigger bias effects. The PT p+p results are consistent with the MB p+p data for trigger GeV/.

The jet associated partner yield per trigger, , is obtained from the correlations as  Adler:2005ad ; Adler:2005ee :

(1)

where is the number of triggers, is the single particle efficiency for partners in the full azimuth and ; and are pair distributions from the same- and mixed-events, respectively. Mixed-event pairs are obtained by selecting partners from different events with similar centrality and vertex. The values include detector acceptance and reconstruction efficiency, with an uncertainty of Adler:2005in ; Adler:2003au . The harmonic term, , reflects the elliptic flow modulation of the combinatoric pairs in Au+Au collisions Adler:2005ee . Values for and for each centrality class are measured via the reaction plane (RP) method Adler:2003kt using the Beam-Beam Counters at . The systematic errors on are dominated by the RP resolution, and are estimated to be % for central and mid-central collisions, and % for the peripheral collisions Adler:2005ee .

To fix the value of , we followed the subtraction procedure of Refs. Adler:2005ee ; Ajitanand:2005jj and assumed that has zero yield at its minimum (ZYAM). To estimate the possible over-subtraction at , we calculate values independently by fitting to a function consisting of one near-side and two symmetric away-side Gaussians. The fitting procedure is similar to that used in Adare:2006nr , except that a region around () is excluded to avoid “punch-through” jets around (see Fig.1). This fit accounts for the overlap of the near- and away-side Gaussians at , and thus gives systematically lower values than that for ZYAM. We assign the differences as one-sided systematic errors on . This over-subtraction error is only significant in central collisions and at GeV/.

The per-trigger yield distributions for and 0-20% central Au+Au collisions are compared in Fig. 1 for various combinations of trigger and partner ranges () as indicated. The data show essentially Gaussian away-side peaks centered at for all and . In contrast, the Au+Au data show substantial shape modifications dependent on and . For a fixed value of , Figs. 1(a)-(d) reveal a striking evolution from a broad, roughly flat peak to a local minimum at with side-peaks at . Interestingly, the location of the side-peaks in is roughly constant with increasing (see also Adare:2006nr ). Such independence is compatible with the away-side jet modification expected from a medium-induced “Mach Shock” Casalderrey-Solana:2004qm but disfavors models which incorporate large angle gluon radiation Vitev:2005yg ; Polosa:2006hb , Cherenkov gluon radiation Koch:2005sx or deflected jets Armesto:2004pt ; Chiu:2006pu .

Figure 1: Per-trigger yield versus for various trigger and partner (), arranged by increasing pair momentum (sum of and ), in and 0-20% Au+Au collisions. The Data in some panels are scaled as indicated. Solid lines (shaded bands) indicate elliptic flow (ZYAM) uncertainties. Arrows in (c) indicate “head” (HR) and “shoulder” (SR) regions.

For relatively high values of , Figs. 1(e)-(h) show that the away-side jet shape for Au+Au gradually becomes peaked as for , albeit suppressed. This “re-appearance” of the away-side peak seems due to a reduction of the yield centered at relative to that at , rather than a merging of the peaks centered at . This is consistent with the dominance of dijet fragmentation at large , possibly due to jets that “punch-through” the medium Renk:2006pk or those emitted tangentially to the medium’s surface Loizides:2006cs .

The evolution of the away-side jet shape with (cf. Fig. 1) suggests separate contributions from a medium-induced component centered at and a fragmentation component centered at . A model independent study of these contributions can be made by dividing the away-side jet function into equal-sized “head” (, HR) and “shoulder” (, SR) regions, as indicated in Fig. 1(c). We characterize the relative amplitude of these two regions with the ratio, ,

(2)

Since in Eq.1 cancels in the ratio, is a pure pair variable and is symmetric and : . For concave and convex shapes, one expects and , respectively.

Figure 2: versus for (open) and Au+Au (filled) collisions for four trigger selections. Since is purely hadron pair variable, the result is unchanged by swapping and . Shaded bars (brackets) represent -correlated uncertainties due to elliptic flow (ZYAM procedure).

Figure 2 summarizes the dependence of for both and central Au+Au collisions in four bins. The ratios for are always above one and increase with . This reflects the narrowing of a peaked jet shape with increasing  Adler:2005ad . In contrast, the ratios for Au+Au show a non-monotonic dependence on . They evolve from for GeV/ through for GeV/ followed by for GeV/. These trends reflect the competition between medium-induced modification and jet fragmentation, and suggest that the latter dominates at GeV/. The results shown in Fig. 1 indicate that, relative to , the Au+Au yield is suppressed in the HR but is enhanced in the SR. We quantify this suppression/enhancement via , the ratio of jet yield between Au+Au and collisions over a region, W, .

Figure 3 shows as a function of for the HR and the HR+SR, respectively, in four bins. For triggers of GeV/, for HR+SR exceeds one at low , but falls and crosses one at 3.5 GeV/. A similar trend is observed for the higher triggers, but the enhancement (at low ) is smaller and the suppression (at high ) is stronger. The values in HR are lower relative to HR+SR for all . For the low triggers, the suppression sets in around GeV/, followed by a fall-off for GeV/. For higher triggers, a constant level of is observed above GeV/ similar to the suppression level of inclusive hadrons Adler:2003au . These results provide clear evidence for significant yield enhancement in the SR and suppression in the HR. The data suggest that the SR reflects the dissipative processes that redistribute the energy lost in the medium; The suppression for the HR is consistent with jet quenching. However, we note that the values for the HR are upper limit estimates for the jet fragmentation component. This is because the HR yield includes possible contributions from the tails of the SR, as well as from bremsstrahlung gluon radiations Vitev:2005yg .

Figure 3: versus for four trigger bins in HR+SR () and HR (). The total systematic errors for the two regions, represented by shaded bars and brackets respectively, are strongly correlated. Grey bands around represent 14% combined uncertainty on the single particle efficiency in Au+Au and .

To further explore the interplay between the HR and the SR, we focus on the intermediate region, GeV/, where the medium-induced component dominates the away-side yield. We characterize the inverse local slope of the partner yield in this range via a truncated mean , - 1 GeV/. is calculated from the jet yields used to make in Fig. 3. Fig. 4 shows the values for the HR, SR and a near-side region (, NR), as a function of the number of participating nucleons, . The values for NR have a weak centrality dependence. Their overall levels for are , and GeV/ for the ranges 2-3, 3-4 and 4-5 GeV/, respectively ridge . This finding is consistent with the dominance of jet fragmentation on the near-side, i.e. a harder spectrum for partner hadrons is expected for higher trigger hadrons.

A very weak centrality dependence is observed for the SR for . In this case, the values for are lower ( GeV/) and do not depend on . They are, however, larger than the values measured for inclusive charged hadrons (0.38 GeV/ shown by solid lines) Adler:2003au . The relatively sharp increase in for may reflect a significant jet fragmentation contribution in peripheral collisions. In contrast, the values for the HR show a gradual decrease with , starting close to that for the near-side jet, and approaches the value for the inclusive spectrum for .

Figure 4: Truncated mean in GeV/ versus for the near-side (diamonds), away-side shoulder (circles) and head (squares) regions for Au+Au (filled) and p+p (open) for three trigger bins. Solid lines represent measured values for inclusive charged hadrons Adler:2003au . Error bars represent the statistical errors. Shaded bars represent the sum of -correlated elliptic flow and ZYAM error.

The different patterns observed for the yields in the HR and SR suggest a different origin for these yields. The suppression of the HR yield and the softening of its spectrum are consistent with a depletion of yield due to jet quenching. The observed HR yield could be comprised of contributions from “punch-through” jets, radiated gluons and feed-in from the SR. By contrast, the enhancement of the SR yield for GeV/ suggests a remnant of the lost energy from quenched jets. However, the very weak dependence on and centrality (for ) for its peak location and mean may reflect an intrinsic property of the response of the medium to the energetic jets. These observations are inconsistent with simple deflected jet Armesto:2004pt ; Chiu:2006pu and Cherenkov gluon radiation Koch:2005sx models, since both the deflection/radiation angle and jet spectra slope would depend on the or . However, these results are consistent with expectations for “Mach Shock” in a near-ideal hydrodynamical medium  Renk:2005si ; Casalderrey-Solana:2004qm , and thus they can be used to constrain medium transport properties such as speed of sound and viscosity to entropy ratio.

In conclusion, we have observed strong medium modification of away-side shapes and yields for jet-induced pairs in Au+Au collisions at =200 GeV. The detailed dependence of these results on and centrality gives strong evidence for two distinct contributions from the regions of and . The former is consistent with jet quenching. The latter exhibits and centrality independent shape and mean , possibly reflecting an intrinsic property of the medium response to energetic jets. These results provide strong constraints on competing mechanisms for the energy transport.

We thank the staff of the Collider-Accelerator and Physics Departments at BNL for their vital contributions. We acknowledge support from the Department of Energy and NSF (U.S.A.), MEXT and JSPS (Japan), CNPq and FAPESP (Brazil), NSFC (China), MSMT (Czech Republic), IN2P3/CNRS and CEA (France), BMBF, DAAD, and AvH (Germany), OTKA (Hungary), DAE (India), ISF (Israel), KRF and KOSEF (Korea), MES, RAS, and FAAE (Russia), VR and KAW (Sweden), U.S. CRDF for the FSU, US-Hungarian NSFOTKA- MTA, and US-Israel BSF.

References

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