Low-mass vector-meson production at forward rapidity in p+p collisions at \sqrt{s}=200 GeV

Low-mass vector-meson production at forward rapidity in collisions
at GeV

A. Adare University of Colorado, Boulder, Colorado 80309, USA    C. Aidala Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA    N.N. Ajitanand Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    Y. Akiba RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Akimoto Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    H. Al-Ta’ani New Mexico State University, Las Cruces, New Mexico 88003, USA    J. Alexander Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    M. Alfred Department of Physics and Astronomy, Howard University, Washington, DC 20059, USA    K.R. Andrews Abilene Christian University, Abilene, Texas 79699, USA    A. Angerami Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    K. Aoki RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    N. Apadula Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    E. Appelt Vanderbilt University, Nashville, Tennessee 37235, USA    Y. Aramaki Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    R. Armendariz University of California - Riverside, Riverside, California 92521, USA    H. Asano Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    E.C. Aschenauer Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    E.T. Atomssa Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    T.C. Awes Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    B. Azmoun Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    V. Babintsev IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    M. Bai Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    N.S. Bandara Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA    B. Bannier Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    K.N. Barish University of California - Riverside, Riverside, California 92521, USA    B. Bassalleck University of New Mexico, Albuquerque, New Mexico 87131, USA    A.T. Basye Abilene Christian University, Abilene, Texas 79699, USA    S. Bathe Baruch College, City University of New York, New York, New York, 10010 USA RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    V. Baublis PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    C. Baumann Institut fur Kernphysik, University of Muenster, D-48149 Muenster, Germany    A. Bazilevsky Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    M. Beaumier University of California - Riverside, Riverside, California 92521, USA    S. Beckman University of Colorado, Boulder, Colorado 80309, USA    R. Belmont Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA Vanderbilt University, Nashville, Tennessee 37235, USA    J. Ben-Benjamin Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    R. Bennett Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    A. Berdnikov Saint Petersburg State Polytechnic University, St. Petersburg, 195251 Russia    Y. Berdnikov Saint Petersburg State Polytechnic University, St. Petersburg, 195251 Russia    D. Black University of California - Riverside, Riverside, California 92521, USA    D.S. Blau Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    J. Bok New Mexico State University, Las Cruces, New Mexico 88003, USA    J.S. Bok Yonsei University, IPAP, Seoul 120-749, Korea    K. Boyle RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    M.L. Brooks Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    D. Broxmeyer Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    J. Bryslawskyj Baruch College, City University of New York, New York, New York, 10010 USA    H. Buesching Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    V. Bumazhnov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    G. Bunce Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    S. Butsyk Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    S. Campbell Iowa State University, Ames, Iowa 50011, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    P. Castera Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    C.-H. Chen RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    C.Y. Chi Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    M. Chiu Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    I.J. Choi University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA Yonsei University, IPAP, Seoul 120-749, Korea    J.B. Choi Chonbuk National University, Jeonju, 561-756, Korea    R.K. Choudhury Bhabha Atomic Research Centre, Bombay 400 085, India    P. Christiansen Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    T. Chujo Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    O. Chvala University of California - Riverside, Riverside, California 92521, USA    V. Cianciolo Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    Z. Citron Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA Weizmann Institute, Rehovot 76100, Israel    B.A. Cole Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    Z. Conesa del Valle Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    M. Connors Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    M. Csanád ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary    T. Csörgő Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Wigner RCP, RMKI) H-1525 Budapest 114, POBox 49, Budapest, Hungary    S. Dairaku Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    A. Datta Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA University of New Mexico, Albuquerque, New Mexico 87131, USA    M.S. Daugherity Abilene Christian University, Abilene, Texas 79699, USA    G. David Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    M.K. Dayananda Georgia State University, Atlanta, Georgia 30303, USA    K. DeBlasio University of New Mexico, Albuquerque, New Mexico 87131, USA    K. Dehmelt Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    A. Denisov IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    A. Deshpande RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    E.J. Desmond Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    K.V. Dharmawardane New Mexico State University, Las Cruces, New Mexico 88003, USA    O. Dietzsch Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    L. Ding Iowa State University, Ames, Iowa 50011, USA    A. Dion Iowa State University, Ames, Iowa 50011, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    J.H. Do Yonsei University, IPAP, Seoul 120-749, Korea    M. Donadelli Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    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, New York 11794-3800, USA    K.A. Drees Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    J.M. Durham Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    A. Durum IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    L. D’Orazio University of Maryland, College Park, Maryland 20742, USA    Y.V. Efremenko Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    T. Engelmore Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    A. Enokizono Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan    H. En’yo RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    S. Esumi Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    B. Fadem Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    N. Feege Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    D.E. Fields University of New Mexico, Albuquerque, New Mexico 87131, USA    M. Finger Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic    M. Finger, Jr. Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic    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, 123098 Russia    J.E. Frantz Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA    A. Franz Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    A.D. Frawley Florida State University, Tallahassee, Florida 32306, USA    Y. Fukao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    T. Fusayasu Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan    C. Gal Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    P. Gallus Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    P. Garg Department of Physics, Banaras Hindu University, Varanasi 221005, India    I. Garishvili University of Tennessee, Knoxville, Tennessee 37996, USA    H. Ge Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    F. Giordano University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    A. Glenn Lawrence Livermore National Laboratory, Livermore, California 94550, USA    X. Gong Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    M. Gonin Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    Y. Goto RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Granier de Cassagnac Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France    N. Grau Department of Physics, Augustana College, Sioux Falls, South Dakota 57197, USA Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    S.V. Greene Vanderbilt University, Nashville, Tennessee 37235, USA    M. Grosse Perdekamp University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    Y. Gu Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    T. Gunji Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    L. Guo Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    H. Guragain Georgia State University, Atlanta, Georgia 30303, USA    H.-Å. Gustafsson Deceased Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    T. Hachiya RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    J.S. Haggerty Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    K.I. Hahn Ewha Womans University, Seoul 120-750, Korea    H. Hamagaki Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    J. Hamblen University of Tennessee, Knoxville, Tennessee 37996, USA    R. Han Peking University, Beijing 100871, P. R. China    S.Y. Han Ewha Womans University, Seoul 120-750, Korea    J. Hanks Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    C. Harper Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    S. Hasegawa Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan    K. Hashimoto RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan    E. Haslum Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    R. Hayano Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    X. He Georgia State University, Atlanta, Georgia 30303, USA    T.K. Hemmick Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    T. Hester University of California - Riverside, Riverside, California 92521, USA    J.C. Hill Iowa State University, Ames, Iowa 50011, USA    R.S. Hollis University of California - Riverside, Riverside, California 92521, USA    W. Holzmann Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    K. Homma Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    B. Hong Korea University, Seoul, 136-701, Korea    T. Horaguchi Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y. Hori Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    D. Hornback Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    T. Hoshino Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    S. Huang Vanderbilt University, Nashville, Tennessee 37235, USA    T. Ichihara RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Ichimiya RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    H. Iinuma KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    Y. Ikeda RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K. Imai Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    Y. Imazu RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    M. Inaba Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    A. Iordanova University of California - Riverside, Riverside, California 92521, USA    D. Isenhower Abilene Christian University, Abilene, Texas 79699, USA    M. Ishihara RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    M. Issah Vanderbilt University, Nashville, Tennessee 37235, USA    D. Ivanischev PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    D. Ivanishchev PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    Y. Iwanaga Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    B.V. Jacak Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    S.J. Jeon Myongji University, Yongin, Kyonggido 449-728, Korea    M. Jezghani Georgia State University, Atlanta, Georgia 30303, USA    J. Jia Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    X. Jiang Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    D. John University of Tennessee, Knoxville, Tennessee 37996, USA    B.M. Johnson Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    T. Jones Abilene Christian University, Abilene, Texas 79699, USA    E. Joo Korea University, Seoul, 136-701, Korea    K.S. Joo Myongji University, Yongin, Kyonggido 449-728, Korea    D. Jouan IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France    D.S. Jumper University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    J. Kamin Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    S. Kaneti Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    B.H. Kang Hanyang University, Seoul 133-792, Korea    J.H. Kang Yonsei University, IPAP, Seoul 120-749, Korea    J.S. Kang Hanyang University, Seoul 133-792, Korea    J. Kapustinsky Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    K. Karatsu Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    M. Kasai RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan    D. Kawall Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    A.V. Kazantsev Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    T. Kempel Iowa State University, Ames, Iowa 50011, USA    J.A. Key University of New Mexico, Albuquerque, New Mexico 87131, USA    V. Khachatryan Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    A. Khanzadeev PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    K. Kihara Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K.M. Kijima Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    B.I. Kim Korea University, Seoul, 136-701, Korea    C. Kim Korea University, Seoul, 136-701, Korea    D.H. Kim Ewha Womans University, Seoul 120-750, Korea    D.J. Kim Helsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI-40014 Jyväskylä, Finland    E.-J. Kim Chonbuk National University, Jeonju, 561-756, Korea    H.-J. Kim Yonsei University, IPAP, Seoul 120-749, Korea    M. Kim Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea    Y.-J. Kim University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    Y.K. Kim Hanyang University, Seoul 133-792, Korea    E. Kinney University of Colorado, Boulder, Colorado 80309, USA    Á. Kiss ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary    E. Kistenev Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    J. Klatsky Florida State University, Tallahassee, Florida 32306, USA    D. Kleinjan University of California - Riverside, Riverside, California 92521, USA    P. Kline Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    T. Koblesky University of Colorado, Boulder, Colorado 80309, USA    L. Kochenda PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    M. Kofarago ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary    B. Komkov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    M. Konno Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    J. Koster University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    D. Kotov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia Saint Petersburg State Polytechnic University, St. Petersburg, 195251 Russia    A. Král Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    G.J. Kunde Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    K. Kurita RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan    M. Kurosawa RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    Y. Kwon Yonsei University, IPAP, Seoul 120-749, Korea    G.S. Kyle New Mexico State University, Las Cruces, New Mexico 88003, USA    R. Lacey Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    Y.S. Lai Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    J.G. Lajoie Iowa State University, Ames, Iowa 50011, USA    A. Lebedev Iowa State University, Ames, Iowa 50011, USA    D.M. Lee Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    J. Lee Ewha Womans University, Seoul 120-750, Korea    K.B. Lee Korea University, Seoul, 136-701, Korea Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    K.S. Lee Korea University, Seoul, 136-701, Korea    S.H. Lee Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    S.R. Lee Chonbuk National University, Jeonju, 561-756, Korea    M.J. Leitch Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    M.A.L. Leite Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    M. Leitgab University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    X. Li Science and Technology on Nuclear Data Laboratory, China Institute of Atomic Energy, Beijing 102413, P. R. China    S.H. Lim Yonsei University, IPAP, Seoul 120-749, Korea    L.A. Linden Levy University of Colorado, Boulder, Colorado 80309, USA    H. Liu Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    M.X. Liu Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    B. Love Vanderbilt University, Nashville, Tennessee 37235, USA    D. Lynch Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    C.F. Maguire Vanderbilt University, Nashville, Tennessee 37235, USA    Y.I. Makdisi Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    M. Makek Weizmann Institute, Rehovot 76100, Israel University of Zagreb, Faculty of Science, Department of Physics, Bijenička 32, HR-10002 Zagreb, Croatia    A. Manion Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    V.I. Manko Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    E. Mannel Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    Y. Mao Peking University, Beijing 100871, P. R. China RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    H. Masui Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M. McCumber University of Colorado, Boulder, Colorado 80309, USA Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    P.L. McGaughey Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    D. McGlinchey University of Colorado, Boulder, Colorado 80309, USA Florida State University, Tallahassee, Florida 32306, USA    C. McKinney University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    N. Means Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    A. Meles New Mexico State University, Las Cruces, New Mexico 88003, USA    M. Mendoza University of California - Riverside, Riverside, California 92521, USA    B. Meredith Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    Y. Miake Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    T. Mibe KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    A.C. Mignerey University of Maryland, College Park, Maryland 20742, USA    K. Miki RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    A.J. Miller Abilene Christian University, Abilene, Texas 79699, USA    A. Milov Weizmann Institute, Rehovot 76100, Israel    D.K. Mishra Bhabha Atomic Research Centre, Bombay 400 085, India    J.T. Mitchell Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    Y. Miyachi RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    S. Miyasaka RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    S. Mizuno RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    A.K. Mohanty Bhabha Atomic Research Centre, Bombay 400 085, India    P. Montuenga University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    H.J. Moon Myongji University, Yongin, Kyonggido 449-728, Korea    T. Moon Yonsei University, IPAP, Seoul 120-749, Korea    Y. Morino Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    A. Morreale University of California - Riverside, Riverside, California 92521, USA    D.P. Morrison morrison@bnl.gov Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    S. Motschwiller Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    T.V. Moukhanova Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    T. Murakami Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    J. Murata RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan    A. Mwai Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    S. Nagamiya KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    J.L. Nagle jamie.nagle@colorado.edu University of Colorado, Boulder, Colorado 80309, USA    M. Naglis Weizmann Institute, Rehovot 76100, Israel    M.I. Nagy ELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, Hungary Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Wigner RCP, RMKI) H-1525 Budapest 114, POBox 49, Budapest, Hungary    I. Nakagawa RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    H. Nakagomi RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y. Nakamiya Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    K.R. Nakamura Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    T. Nakamura RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    K. Nakano RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan    C. Nattrass University of Tennessee, Knoxville, Tennessee 37996, USA    P.K. Netrakanti Bhabha Atomic Research Centre, Bombay 400 085, India    J. Newby Lawrence Livermore National Laboratory, Livermore, California 94550, USA    M. Nguyen Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    M. Nihashi Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    T. Niida Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    R. Nouicer Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    N. Novitzky Helsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI-40014 Jyväskylä, Finland    A.S. Nyanin Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    C. Oakley Georgia State University, Atlanta, Georgia 30303, USA    E. O’Brien Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    C.A. Ogilvie Iowa State University, Ames, Iowa 50011, USA    M. Oka Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K. Okada RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    J.D. Orjuela Koop University of Colorado, Boulder, Colorado 80309, USA    A. Oskarsson Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    M. Ouchida Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    H. Ozaki Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K. Ozawa Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    R. Pak Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    V. Pantuev Institute for Nuclear Research of the Russian Academy of Sciences, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, Russia Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    V. Papavassiliou New Mexico State University, Las Cruces, New Mexico 88003, USA    B.H. Park Hanyang University, Seoul 133-792, Korea    I.H. Park Ewha Womans University, Seoul 120-750, Korea    S. Park Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea    S.K. Park Korea University, Seoul, 136-701, Korea    S.F. Pate New Mexico State University, Las Cruces, New Mexico 88003, USA    L. Patel Georgia State University, Atlanta, Georgia 30303, USA    M. Patel Iowa State University, Ames, Iowa 50011, USA    H. Pei Iowa State University, Ames, Iowa 50011, USA    J.-C. Peng University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    H. Pereira Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    D.V. Perepelitsa Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    G.D.N. Perera New Mexico State University, Las Cruces, New Mexico 88003, USA    D.Yu. Peressounko Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    J. Perry Iowa State University, Ames, Iowa 50011, USA    R. Petti Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    C. Pinkenburg Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Pinson Abilene Christian University, Abilene, Texas 79699, USA    R.P. Pisani Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    M. Proissl Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    M.L. Purschke Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    H. Qu Georgia State University, Atlanta, Georgia 30303, USA    J. Rak Helsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI-40014 Jyväskylä, Finland    I. Ravinovich Weizmann Institute, Rehovot 76100, Israel    K.F. Read Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA University of Tennessee, Knoxville, Tennessee 37996, USA    K. Reygers Institut fur Kernphysik, University of Muenster, D-48149 Muenster, Germany    D. Reynolds Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    V. Riabov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    Y. Riabov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia Saint Petersburg State Polytechnic University, St. Petersburg, 195251 Russia    E. Richardson University of Maryland, College Park, Maryland 20742, USA    N. Riveli Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA    D. Roach Vanderbilt University, Nashville, Tennessee 37235, USA    G. Roche LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France    S.D. Rolnick University of California - Riverside, Riverside, California 92521, USA    M. Rosati Iowa State University, Ames, Iowa 50011, USA    S.S.E. Rosendahl Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    Z. Rowan Baruch College, City University of New York, New York, New York, 10010 USA    J.G. Rubin Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA    B. Sahlmueller Institut fur Kernphysik, University of Muenster, D-48149 Muenster, Germany Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    N. Saito KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    T. Sakaguchi Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    H. Sako Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan    V. Samsonov PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, Russia    S. Sano Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    M. Sarsour Georgia State University, Atlanta, Georgia 30303, USA    S. Sato Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan    T. Sato Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M. Savastio Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    S. Sawada KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    B. Schaefer Vanderbilt University, Nashville, Tennessee 37235, USA    B.K. Schmoll University of Tennessee, Knoxville, Tennessee 37996, USA    K. Sedgwick University of California - Riverside, Riverside, California 92521, USA    J. Seele RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Seidl RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    A. Sen University of Tennessee, Knoxville, Tennessee 37996, USA    R. Seto University of California - Riverside, Riverside, California 92521, USA    P. Sett Bhabha Atomic Research Centre, Bombay 400 085, India    A. Sexton University of Maryland, College Park, Maryland 20742, USA    D. Sharma Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA Weizmann Institute, Rehovot 76100, Israel    I. Shein IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    T.-A. Shibata RIKEN Nishina Center for Accelerator-Based Science, 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    H.H. Shim Korea University, Seoul, 136-701, Korea    M. Shimomura Iowa State University, Ames, Iowa 50011, USA Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    K. Shoji Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    P. Shukla Bhabha Atomic Research Centre, Bombay 400 085, India    A. Sickles Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    C.L. Silva Iowa State University, Ames, Iowa 50011, USA Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    D. Silvermyr Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    C. Silvestre Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France    K.S. Sim Korea University, Seoul, 136-701, Korea    B.K. Singh Department of Physics, Banaras Hindu University, Varanasi 221005, India    C.P. Singh Department of Physics, Banaras Hindu University, Varanasi 221005, India    V. Singh Department of Physics, Banaras Hindu University, Varanasi 221005, India    M. Slunečka Charles University, Ovocný trh 5, Praha 1, 116 36, Prague, Czech Republic    T. Sodre Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA    R.A. Soltz Lawrence Livermore National Laboratory, Livermore, California 94550, USA    W.E. Sondheim Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    S.P. Sorensen University of Tennessee, Knoxville, Tennessee 37996, USA    I.V. Sourikova Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    P.W. Stankus Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    E. Stenlund Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden    M. Stepanov Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA    S.P. Stoll Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    T. Sugitate Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    A. Sukhanov Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    T. Sumita RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    J. Sun Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    J. Sziklai Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Wigner RCP, RMKI) H-1525 Budapest 114, POBox 49, Budapest, Hungary    E.M. Takagui Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil    A. Takahara Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    A. Taketani RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R. Tanabe Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y. Tanaka Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan    S. Taneja Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    K. Tanida Kyoto University, Kyoto 606-8502, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea    M.J. Tannenbaum Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    S. Tarafdar Department of Physics, Banaras Hindu University, Varanasi 221005, India Weizmann Institute, Rehovot 76100, Israel    A. Taranenko Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    E. Tennant New Mexico State University, Las Cruces, New Mexico 88003, USA    H. Themann Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    D. Thomas Abilene Christian University, Abilene, Texas 79699, USA    R. Tieulent Georgia State University, Atlanta, Georgia 30303, USA    A. Timilsina Iowa State University, Ames, Iowa 50011, USA    T. Todoroki RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M. Togawa RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    L. Tomášek Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    M. Tomášek Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic    H. Torii Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    M. Towell Abilene Christian University, Abilene, Texas 79699, USA    R. Towell Abilene Christian University, Abilene, Texas 79699, USA    R.S. Towell Abilene Christian University, Abilene, Texas 79699, USA    I. Tserruya Weizmann Institute, Rehovot 76100, Israel    Y. Tsuchimoto Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    K. Utsunomiya Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan    C. Vale Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    H.W. van Hecke Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA    M. Vargyas Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Wigner RCP, RMKI) H-1525 Budapest 114, POBox 49, Budapest, Hungary    E. Vazquez-Zambrano Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    A. Veicht Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    J. Velkovska Vanderbilt University, Nashville, Tennessee 37235, USA    R. Vértesi Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Wigner RCP, RMKI) H-1525 Budapest 114, POBox 49, Budapest, Hungary    M. Virius Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic    A. Vossen University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    V. Vrba Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic 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    X.R. Wang New Mexico State University, Las Cruces, New Mexico 88003, USA    D. Watanabe Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan    K. Watanabe Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y. Watanabe RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    Y.S. Watanabe Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan    F. Wei Iowa State University, Ames, Iowa 50011, USA New Mexico State University, Las Cruces, New Mexico 88003, USA    R. Wei Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA    J. Wessels Institut fur Kernphysik, University of Muenster, D-48149 Muenster, Germany    S. Whitaker Iowa State University, Ames, Iowa 50011, USA    S.N. White Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    D. Winter Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    S. Wolin University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    C.L. Woody Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    R.M. Wright Abilene Christian University, Abilene, Texas 79699, USA    M. Wysocki University of Colorado, Boulder, Colorado 80309, USA Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    B. Xia Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA    L. Xue Georgia State University, Atlanta, Georgia 30303, USA    S. Yalcin Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA    Y.L. Yamaguchi Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan    R. Yang University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA    A. Yanovich IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia    J. Ying Georgia State University, Atlanta, Georgia 30303, USA    S. Yokkaichi RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    J.S. Yoo Ewha Womans University, Seoul 120-750, Korea    I. Yoon Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea    Z. You Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA Peking University, Beijing 100871, P. R. China    G.R. Young Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA    I. Younus Physics Department, Lahore University of Management Sciences, Lahore 54792, Pakistan University of New Mexico, Albuquerque, New Mexico 87131, USA    I.E. Yushmanov Russian Research Center “Kurchatov Institute”, Moscow, 123098 Russia    W.A. Zajc Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA    A. Zelenski Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA    S. Zhou Science and Technology on Nuclear Data Laboratory, China Institute of Atomic Energy, Beijing 102413, P. R. China
July 19, 2019
Abstract

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low mass vector meson, , , and , production through the dimuon decay channel at forward rapidity () in collisions at  GeV. The differential cross sections for these mesons are measured as a function of both and rapidity. We also report the integrated differential cross sections over GeV/ and :  nb and  nb. These results are compared with midrapidity measurements and calculations.

pacs:
13.20.Jf, 25.75.Dw

PHENIX Collaboration

I Introduction

Low-mass vector meson (LVM) production in collisions is an important tool to study quantum chromodynamics (QCD), providing data to tune phenomenological soft QCD models and to compare to hard perturbative QCD calculations. Various experiments Abelev et al. (2009a); Adare et al. (2011a); Alexopoulos et al. (1995); Abelev et al. (2012a); Abelev et al. (2012b); Aaij et al. (2011) have studied LVM at different colliding energies and in different kinematic regions.

In addition, LVM production in collisions provides a reference for high-energy heavy-ion-collision measurements. LVM studies provide key information on the hot and dense state of the strongly interacting matter produced in such collisions. Among them, strangeness enhancement Koch et al. (1986), a phenomenon associated with soft particles in bulk matter, can be accessed through the measurements of -meson production Alt et al. (2008); Alessandro et al. (2003); Adamová et al. (2006); Arnaldi et al. (2011); Adare et al. (2011b); Abelev et al. (2009b) and the /() ratio. The measurement of the spectral function can be used to reveal in-medium modifications of the hadron properties close to the QCD phase boundary linked to chiral symmetry restoration van Hees and Rapp (2008); Adamová et al. (2008); Arnaldi et al. (2006). However, measuring the spectral function in the two-muon channel requires better mass resolution than is provided by the muon spectrometers of the PHENIX experiment at the Relativistic Heavy Ion Collider.

Having two muon spectrometers covering the rapidity range , PHENIX is able to study vector-meson production via the dimuon decay channel. Because there is no similar measurement in this kinematic regime at this energy, the forward rapidity measurements are a valuable addition to the database and are complementary to previously published midrapidity results Abelev et al. (2009a); Adare et al. (2011a). We report the differential cross section as a function of and rapidity of and mesons for  GeV/ and . Results presented in this paper are based on the data sample collected in 2009 using the PHENIX muon spectrometers in collisions at  = 200 GeV. The sampled luminosity of the data used in this analysis corresponds to 14.1 pb.

Ii Experiment

The PHENIX apparatus is described in detail in Adcox et al. (2003). This analysis uses the dimuon decay channel of the low mass vector mesons. The detectors relevant for reconstruction and triggering are the two muon spectrometers Aronson et al. (2003) and the two beam-beam counters (BBCs) in the forward and backward rapidities.

The muon spectrometers, located behind an absorber composed of 19 cm copper and 60 cm iron, include the muon tracker (MuTr), which is in a radial magnetic field with an integrated bending power of 0.8 Tesla-meter, followed by the muon identifier (MuID). The muon spectrometers cover the range over the full azimuth. The MuTr comprises three sets of cathode strip chambers while the MuID comprises five planes of Iarocci tubes interleaved with steel absorber plates. The composite momentum resolution, , of particles in the analyzed momentum range is about 5% independent of momentum and dominated by multiple scattering, and the LVM mass resolution is 85 MeV/. Muon candidates are identified by reconstructed tracks in the MuTr matched to MuID tracks that penetrate through to the last MuID plane. The minimum momentum of a muon to reach the last MuID plane is 2 GeV/.

Beam-beam counters (BBC), consisting of two arrays of 64 Čerenkov counters covering the pseudorapidity range , were used to measure the collision vertex along the beam axis () with 2-cm resolution in addition to providing a minimum-bias trigger.

Iii Data Analysis

The data set for this analysis was recorded in 2009 using a minimum-bias trigger that required at least one hit in each of the BBCs. Additionally, the MuID Level-1 dimuon trigger was used which required that at least two tracks penetrate through the MuID to its last layer.

A set of quality assurance cuts is applied to the data to select good muon candidates and improve the signal to background ratio. The BBC collision z vertex is required to be within 30 cm of the center of the interaction region along the beam direction. The MuTr tracks are matched to the MuID tracks at the first MuID layer in both position and angle. In addition, the track trajectory is required to have at least 8 of 10 possible hits in the MuID.

The invariant mass distribution is formed by combining muon candidate tracks of opposite charge. In addition to low mass vector mesons, the invariant mass spectra contains uncorrelated and correlated backgrounds. The uncorrelated backgrounds arise from random combinatoric associations of unrelated muons candidates while the correlated backgrounds arise from open charm decay (e.g., where both decay semileptonically to muons), open bottom decay, and Dalitz decays and the Drell-Yan process.

Traditionally, the combinatorial background is estimated and subtracted by two methods. The first method uses the mass spectra of the like-sign pairs that are reconstructed within the same event. The other forms unlike-sign and like-sign pairs from different events and is often referred to as the “mixed-event method.” In the like-sign method, the like-sign pairs are expected to originate from combinatorial processes; in addition there can be correlated pairs within a single event Adare et al. (2011c). In the case of the mixed event method, unlike-sign pairs are formed from tracks from different events which provides purely combinatorial pairs Adare et al. (2011c, 2013). The results of using these two methods are shown in Fig. 1.

Figure 1: (color online) The unlike-sign dimuon invariant mass spectrum before background subtraction (solid black points), after subtracting mixed events background (empty red triangles) and after subtracting like-sign background (empty blue circles).

It is clear from Fig. 1 that the two methods are not able to reproduce the background in the low mass region. Hence, we introduce a new data driven technique here.

The background below 1.4 GeV/ is dominated by

  1. decays that occur before reaching the absorber

  2. punch-through hadrons with high that are misidentified as muons and

  3. muons that result from decay in the muon tracker volume.

A statistic is calculated from a simultaneous fit of the two muon tracks with a common event determined by the BBC. Tracks due to the backgrounds listed above produce a broader distribution than that of true muon tracks, and this difference can be used to discriminate statistically between foregrounds and backgrounds. We classify pairs with as foreground pairs and those with as background pairs. The value, , was selected such that we retain as much of the signal as possible, while still allowing enough statistics in our background sample.

Figure 2: (color online) The distributions for nonresonant mass region (red), and signal () mass region (blue) The unlike-sign pairs are shown in (a) while the like-sign pairs are shown in (b). In each panel, the histograms are normalized to the total number of events.

Figure 2(a) shows the unlike-sign pairs distribution, which is narrower in the resonance region dominated by prompt dimuons (e.g, in the region,  GeV/), and wider in the nonresonant regions. On the other hand, the distribution for the like-sign pairs is the same in both mass regions. In addition, the unlike-sign distribution matches very well that of the like-sign in the nonresonant region. After selecting the foreground and background from the data, the background is normalized to the foreground by two normalization methods: The first method uses the unlike-sign pairs, where the ratio of the foreground to background spectra is fitted by a polynomial in the nonresonant region and the background spectra are then multiplied by the fit function. The other uses the ratio of like-sign pairs corresponding to and to determine the functional form of the shape of the background. This function is then normalized to match the unlike-sign distribution in the nonresonant regions,  GeV/ and  GeV/. Background estimates using those two methods are shown in Fig. 3.

Figure 3: (color online) The unlike-sign dimuon invariant mass spectrum (solid red points) and the background spectrum (empty blue circles) normalized using the first normalization method in (a) while using the second normalization method in (b). The insert in (b) shows the muon arms acceptance and reconstruction efficiency.

Both estimates of the background match the nonresonant region of the unlike-sign spectrum. However, because the second method includes a two-step normalization which introduces higher statistical fluctuations upon the background subtraction, the second method is only used for a cross check. The insert in Fig. 3(b) shows that the acceptance and reconstruction efficiency drops quickly at low mass which explains the higher yield compared to the low mass vector mesons.

To ensure the robustness of the yield extraction, an additional yield extraction procedure is employed. The background is fitted with a polynomial and the result of the fit is added to signal fits which are then fitted to the dimuon invariant mass spectrum while constraining the added function with the background spectra fit parameters. The background normalization is a free parameter.

The unlike-sign dimuon spectra, with , in the region of interest ( GeV/) have contributions from three mesons, , , and . The meson is partly resolved while and mesons are completely merged, hence the combined yield for and mesons was extracted. It was found that the reconstructed mass spectra of the simulated and are fitted well by Gaussian distributions, while in the case of , a Breit Wigner distribution matched the mass spectrum, which motivated using these distributions to fit the invariant mass spectra.

The background subtracted dimuon spectra in the low mass region, GeV/, are fitted with two Gaussian distributions and a Breit Wigner distribution. The means and widths ( for Breit Wigner distribution) of the reconstructed , and were extracted using the PHENIX simulation chain and used as a first approximation in fitting the data. The masses and widths are free parameters in the fit to account for small detector effects which result in % variations with respect to the PDG values. In addition to these distributions, the dimuon spectra without background subtraction are fitted with a polynomial. It is important to note that the parameters from data and simulation fits converged to the same values within uncertainties without any systematic shifts.

Figure 4: (color online) Raw unlike-sign dimuon spectra (solid black circles) along with normalized background (empty blue circles) separated by in (a). Panel (b) shows the normalized background spectrum fitted with a fourth order polynomial. Panels (c) and (d) show the fitted spectra with (left) and without (right) background subtraction.

Figure 4 shows an example of the different yield extraction methods. Figure 4(a) shows the unlike-sign dimuon invariant mass spectrum (solid black circles) and the background spectrum (empty blue circles), while (b) shows the same background spectrum fitted with a fourth order polynomial. Figure 4(c) shows the unlike-sign dimuon invariant mass spectrum after subtracting the normalized background spectrum, shown in (b), fitted by two Gaussian distributions and a Breit Wigner distribution. s a cross check, a first order polynomial was added to the fit and the yields re-extracted and the resulting yields changed by less than 1%. Figure 4(d) shows the unlike-sign dimuon invariant mass spectrum without background subtraction fitted by two Gaussian distributions, a Breit Wigner distribution and a fourth order polynomial constrained from the fit results shown in Fig. 4(b). The yields extracted using the two methods illustrated in Fig. 4(c) and (d) gave consistent results, well within uncertainties.

The data are binned as a function of over the range GeV/ for the rapidities . In addition, the data integrated over the range GeV/ were studied as a function of rapidity. The raw yields in this measurement were extracted using background subtraction as well as background fit methods, and in the case of the background fit, several polynomials of different orders were attempted. As an example, the invariant mass spectra are fitted by the function that includes a fourth order polynomial, as defined below,

(1)

where and are a Breit-Wigner and a Gaussian functions, respectively, and is a fourth order polynomial. and are the yields of and , and and are their mean values. The fit functions of (Gaussian) and (Breit Wigner) are constrained to have the same mean value and the ratio of their yields, is set to 0.58. The factor 0.58 is the ratio of and cross sections,  Adare et al. (2010), multiplied by the ratio of their branching ratios Beringer et al. (2012). The results of fitting the invariant mass spectra for different bins at are listed in Table 1.

(GeV/) 1.0 - 2.0 2.0 - 2.5 2.5 - 3.0 3.0 - 4.5 4.5 - 7.0
(68 5) (63 8) (39 4) (36 5) (4.8 1.2)
(GeV/) (77 1) (77 1) (77 1) (76 1) (80 2)
(GeV/) (18 4) (22 4) (22 2) (18 4) (19 2)
(GeV/) (8.8 1.3) (85 8) (8.8 1.2) (8.1 1.3) (7.2 1.6)
(39 8) (53 6) (32 4) (28 3) 38 10
(GeV/) (100 1) (99 1) (100 1) (100 2) (106 6)
(GeV/) (7.5 1.4) (8.8 1.3) (8.8 1.1) (8.8 1.0) (7.2 1.1)
p0 (20 4) (5.9 3.8) (13 3) (9.5 2.8) 8.6 1.3
p1 (-3.8 2.0) (3.0 1.8) (-2.5 1.3) (-1.8 1.3) -15 2.2
p2 (6.2 3.1) (-4.9 2.5) (3.4 1.8) (2.2 1.8) 39 1.5
p3 (-3.6 2.0) (2.6 1.4) (-2.1 1.0) (-1.3 1.0) -35 1
p4 (6.7 4.3) (-4.7 2.9) (4.6 2.1) (2.6 2.1) 9.2 0.4
/ndf 43.2/33 28.1/33 24.7/33 29.2/33 39.7/33
Table 1: The results of fitting the foreground spectrum by a function that includes two Gaussian distributions, a Breit Wigner distribution and a fourth order polynomial, over the mass range  GeV/ for the listed bins.

The extracted yields of and were consistent among all fits. Therefore, the yields and their uncertainties of the fit with the best are used in the differential cross section calculations. The variations between the yields of the fit with the best and those of the other fits are considered as systematic uncertainties on the yield extraction.

The acceptance and reconstruction efficiency () of the muon spectrometers, including the MuID trigger efficiency, is determined by individually running pythia 6.421 (Default) Sjostrand et al. (2001) generated , , and through a full geant simulation of the PHENIX detector. The simulated vertex distribution was tuned to match that of the 2009 data. The simulated events are reconstructed in the same manner as the data and the same cuts are applied as in the real data analysis.

Figure 5: (color online) The as a function of rapidity (-axis) and (-axis) for .

The and rapidity distributions of the generated events match the measured ones very well. The insert in Fig. 3 shows the as a function of invariant mass, while Fig. 5 shows the as a function of and rapidity for , as an example; the for and look very similar. The dependent drops quickly at lower which is the reason for limiting this study to GeV/.

Iv Results

The differential cross section is evaluated according to the following relation:

(2)

where is the PHENIX BBC sampled cross section, mb at GeV, which is determined from the van der Meer scan technique Adare et al. (2009). is the branching ratio to dimuons (, , and Beringer et al. (2012). = , is the BBC efficiency for hard scattering events Adler et al. (2004). is the number of MB events, and is the number of the observed mesons. In the dependent study, the LVM yields were extracted for each arm separately and the weighted average of the two arms was used in the differential cross section calculations. is the acceptance and reconstruction efficiency.

The and yields are measured together and the dependent and rapidity dependent differential cross sections are reported as and , respectively, to minimize the contribution of uncertainties from branching ratios and total cross sections needed to calculate the absolute () differential cross section. The for is taken as the weighted average of the individual , where the averaging is done based on and branching ratios.

The systematic uncertainties associated with this measurement can be divided into three categories based upon the effect each source has on the measured results. All uncertainties are reported as standard deviations. Type-A : point-to-point uncorrelated uncertainties allow the data points to move independently with respect to one another and are added in quadrature with statistical uncertainties, and include a 3% signal extraction uncertainty. Type-B : point-to-point correlated uncertainties allow the data points to move coherently within the quoted range. These systematic uncertainties include a 4% uncertainty from MuID tube efficiency and 2% from MuTr overall efficiency. An 8% uncertainty on the yield is assigned to account for a 2% absolute momentum scale uncertainty, which was estimated by measuring the mass. A 9% (7%) uncertainty is assigned to the () rapidity due to the uncertainties in the determination method itself. The at the lowest bin is small, as shown in Fig. 5, and sensitive to variations in the slope of the input distribution which affects the differential cross section calculations at this bin. To understand this effect, the -dependent cross section is fitted by three commonly used fit functions (Hagedorn Hagedorn (1965), Kaplan Kaplan et al. (1978), and Tsallis Adare et al. (2011a)) over the range , GeV/, and the fitted functions are extrapolated to lowest bin, GeV/. The differences between the values extracted from these fits and the measured one at the lowest bin is within 8%, hence an 8% systematic uncertainty is assigned to lowest bin to account for these differences. For the integrated and rapidity dependent cross sections the 8% uncertainty is assigned to all data bins because the lowest bin is dominant. Type-B systematic uncertainties are added in quadrature and are shown as shaded bands on the associated data points. Finally, an overall normalization uncertainty of 10% was assigned for the BBC cross section and efficiency uncertainties which allows the data points to move together by a common multiplicative factor, and are labeled as type-C. These systematic uncertainties are listed in Table 2.

Type Origin Value (S/N)
A Signal extraction 3%
B MuID efficiency 4%
B MuTr efficiency 2%
B 9% / 7%
B Absolute momentum scale 8%
Total Quadratic sum of (B) 13% / 12%
C BBC efficiency (Global) 10%
Table 2: Systematic uncertainties included in the invariant yield and differential cross section calculations, where S (N) is for the () rapidity. As explained in the text, there is an 8% type-B systematic uncertainty due to small acceptance that impacts the low region only which is not listed below.
Figure 6: (color online) (top) dependent differential cross sections of at rapidity, . The error bars represent the statistical uncertainties, and the gray shaded band represents the quadratic sum of type-B systematic uncertainties. The data are compared with the pythia atlas-csc, default and prugia-11 tunes and phojet. (bottom) Ratio between data and models.
Figure 7: (color online) (top) dependent differential cross sections of at rapidity, . The error bars represent the statistical uncertainties, and the gray shaded band represents the quadratic sum of type-B systematic uncertainties. The data are compared with the pythia (atlas-csc, default and perugia-11 tunes and phojet. (bottom) Ratio between data and models.
Figure 6: (color online) (top) dependent differential cross sections of at rapidity, . The error bars represent the statistical uncertainties, and the gray shaded band represents the quadratic sum of type-B systematic uncertainties. The data are compared with the pythia atlas-csc, default and prugia-11 tunes and phojet. (bottom) Ratio between data and models.
Figure 8: (color online) (top) dependent differential cross sections of at rapidity,  Adare et al. (2011a). The data are compared with the pythia atlas-csc, default and perugia-11 tunes and phojet. (bottom) Ratio between data and models.
Figure 9: (color online) (top) dependent differential cross sections of at rapidity,  Adare et al. (2011a). The data are compared with the pythia atlas-csc, default and perugia-11 tunes and phojet. (bottom) Ratio between data and models.
Figure 8: (color online) (top) dependent differential cross sections of at rapidity,  Adare et al. (2011a). The data are compared with the pythia atlas-csc, default and perugia-11 tunes and phojet. (bottom) Ratio between data and models.

The open charm contribution to the signal is a possible source of systematic uncertainty. Even though the background subtracted dimuon spectrum in Fig. 4(c) shows no evidence of a remaining background, a Monte Carlo simulation was carried out to verify that the open charm contribution to the signal is negligible after background subtraction. A single particle pythia simulation of open charm was generated and run through the PHENIX simulation chain. The charm differential cross section at forward rapidity, mb Adler et al. (2007), is used with an inclusive branching ratio, = 0.176 Beringer et al. (2012). The simulated events were then reconstructed using identical code to that used in the real data analysis, and after applying all cuts used in the analysis, the surviving rate of open charm was negligible in comparison to the low mass vector meson yields. Additionally, similar study of the and Dalitz decays showed that they were negligible in comparison to the low mass vector meson yields.

The differential cross sections for and as a function of are shown in Figs. 7 and 7, respectively, and listed in Table 3. The appropriate value where each point was plotted is chosen such that the fit function, a function selected to fit the distribution, is equal to its mean value Lafferty and Wyatt (1995) where the results are listed in the first column in Table 3. Figs. 7 and 7 also include some standard tunes of pythia (atlas-csc Buttar et al. (2004), default Sjostrand et al. (2001) and perugia-11 Skands (2010)) and phojet Engel (1996). The bottom panels in Figs. 7 and 7 show the ratio between the measurement and the model predictions.

(GeV/) (b / (GeV/)) (b / (GeV/))
1.38 (8.41 0.67 1.26) (2.76 0.35 0.41)
2.17 (7.19 0.71 0.93) (3.19 0.36 0.41)
2.65 (1.95 0.19 0.25) (8.16 0.93 1.06)
3.58 (2.68 0.29 0.35) (1.09 0.14 0.14)
5.40 (1.10 0.16 0.14) (4.71 0.90 0.61)
Table 3: Differential cross sections in b/(GeV/) and in (GeV/) of and at with statistical and type-A systematic uncertainties added in quadrature and type-B systematic uncertainties.

These model predictions were also tested against previously published midrapidity data Adare et al. (2011a) as shown in Figs. 9 and 9.

pythia atlas-csc and perugia-11 tunes, reproduce the differential cross section at both midrapidity and forward rapidity for and , respectively, while phojet under predicts the data in both cases. The pythia atlas-csc reproduces the differential cross sections at forward rapidities. The pythia atlas-csc and perugia-11 tunes and phojet fail to match the data below 1 GeV/. Generally, pythia and phojet seem to do better job reproducing than .

Figure 10: (color online) Rapidity dependent differential cross section of (a) and (b) along with previous PHENIX results Adare et al. (2011a) summed over the range, GeV. The error bars represent the quadratic sum of the statistical uncertainties and type-A systematic uncertainties, and the gray shaded band represents the quadratic sum of type-B systematic uncertainties. The data are compared with the pythia atlas-csc and perugia-11 tunes and phojet.
(nb) (nb)
-2.10 61.1 6.7 9.2 21.5 3.7 3.2
-1.84 67.9 5.6 10.2 23.3 2.8 3.5
-1.54 81.0 7.1 12.2 28.1 3.8 4.2
1.54 80.3 7.6 11.2 26.3 3.2 3.7
1.85 66.9 5.4 9.4 21.0 2.8 2.9
2.14 58.4 7.4 8.2 18.9 2.2 2.6
Table 4: Differential cross sections in b and rapidity of and at GeV/ with statistical and type-A systematic uncertainties added in quadrature and type-B systematic uncertainties.
(GeV/)
1.38 0.33 0.04 0.03
2.17 0.44 0.05 0.04
2.65 0.43 0.05 0.04
3.58 0.40 0.05 0.04
5.40 0.45 0.09 0.04
Table 5: and in (GeV/) with statistical and type-A systematic uncertainties added in quadrature and type-B systematic uncertainties.

Figure 10 and Table 4 show the differential cross section as a function of rapidity for in (a) and in (b), along with pythia tunes (atlas-csc, default, and perugia-11) and phojet. It can be seen in Fig. 10 that default and sc perugia-11 tunes reproduce the results, while the atlas-csc tune matches the forward rapidity results.

The acceptance at low is very small to negligible in the low mass region which prevents us from extracting the differential cross sections, , summed over all directly from the data. Instead, we report integrated over the measured range, nb and nb.

The ratio , corrected for acceptance and efficiency, was determined for GeV/ and , giving , as shown in Fig. 11 and listed in Table 5. Systematic uncertainties including MuID and MuTr efficiencies, absolute momentum scale and BBC efficiency cancel out when taking the yield ratio.

Figure 11 also shows pythia (atlas-csc, default, and sc perugia-11 tunes) and phojet. The atlas-csc tune reproduces the ratio while the other models underestimate it. The ALICE experiment also measured this ratio in collisions at 7 TeV in the dimuon rapidity region . The reported value is  Abelev et al. (2012b) over the range which is consistent with our result.

Figure 11: (color online) as a function of . The error bars represent the quadratic sum of the statistical uncertainties and type-A systematic uncertainties, and the gray shaded band represents the quadratic sum of type-B systematic uncertainties.

V Summary and Conclusions

In summary, we studied the low mass vector meson, , , and , production in collisions at = 200 GeV for and GeV/, through the dimuon decay channel. We measured , and differential cross sections as a function of as well as a function of rapidity.

The differential cross sections, of and , were evaluated over the measured range,  nb and  nb. The ratio , at GeV/ and , was also determined, and is , which is consistent with ALICE measurement at larger rapidity and higher energy. This agreement with the ALICE result at , which is higher than pythia default at , suggests a higher contribution to production.

The data are compared to some commonly used pythia tunes and phojet. Overall, the pythia atlas-csc and default tunes describe forward rapidity data except for the rapidity distribution and describe midrapidity data above 1 GeV/. The pythia perugia-11 tune describes the differential cross section while it underestimates the differential cross section. Generally, all these event generators describe the shape of the LVM distribution indicating that leading-order perturbative QCD-based event generators can describe distribution.

Acknowledgments

We thank the staff of the Collider-Accelerator and Physics Departments at Brookhaven National Laboratory and the staff of the other PHENIX participating institutions for their vital contributions. We acknowledge support from the Office of Nuclear Physics in the Office of Science of the Department of Energy, the National Science Foundation, Abilene Christian University Research Council, Research Foundation of SUNY, and Dean of the College of Arts and Sciences, Vanderbilt University (U.S.A), Ministry of Education, Culture, Sports, Science, and Technology and the Japan Society for the Promotion of Science (Japan), Conselho Nacional de Desenvolvimento Científico e Tecnológico and Fundação de Amparo à Pesquisa do Estado de São Paulo (Brazil), Natural Science Foundation of China (P. R. China), Ministry of Science, Education, and Sports (Croatia), Ministry of Education, Youth and Sports (Czech Republic), Centre National de la Recherche Scientifique, Commissariat à l’Énergie Atomique, and Institut National de Physique Nucléaire et de Physique des Particules (France), Bundesministerium für Bildung und Forschung, Deutscher Akademischer Austausch Dienst, and Alexander von Humboldt Stiftung (Germany), OTKA NK 101 428 grant and the Ch. Simonyi Fund (Hungary), Department of Atomic Energy and Department of Science and Technology (India), Israel Science Foundation (Israel), National Research Foundation of Korea of the Ministry of Science, ICT, and Future Planning (Korea), Physics Department, Lahore University of Management Sciences (Pakistan), Ministry of Education and Science, Russian Academy of Sciences, Federal Agency of Atomic Energy (Russia), VR and Wallenberg Foundation (Sweden), the U.S. Civilian Research and Development Foundation for the Independent States of the Former Soviet Union, the Hungarian American Enterprise Scholarship Fund, and the US-Israel Binational Science Foundation.

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