Phys. Rev. Lett.
93,
202002
(2004)
[6 pages]
Double Helicity Asymmetry in Inclusive Midrapidity π0 Production for Polarized p+p Collisions at √s=200 GeV
S. S. Adler et al. PHENIX Collaboration
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S. S. Adler5, S. Afanasiev20, C. Aidala10, N. N. Ajitanand44, Y. Akiba21,40, A. Al-Jamel35, J. Alexander44, K. Aoki25, L. Aphecetche46, R. Armendariz35, S. H. Aronson5, R. Averbeck45, T. C. Awes36, V. Babintsev17, A. Baldisseri11, K. N. Barish6, P. D. Barnes28, B. Bassalleck34, S. Bathe6,31, S. Batsouli10, V. Baublis39, F. Bauer6, A. Bazilevsky5,41, S. Belikov19,17, M. T. Bjorndal10, J. G. Boissevain28, H. Borel11, M. L. Brooks28, D. S. Brown35, N. Bruner34, D. Bucher31, H. Buesching5,31, V. Bumazhnov17, G. Bunce5,41, J. M. Burward-Hoy28,27, S. Butsyk45, X. Camard46, P. Chand4, W. C. Chang2, S. Chernichenko17, C. Y. Chi10, J. Chiba21, M. Chiu10, I. J. Choi53, R. K. Choudhury4, T. Chujo5, V. Cianciolo36, Y. Cobigo11, B. A. Cole10, M. P. Comets37, P. Constantin19, M. Csanád13, T. Csörgő22, J. P. Cussonneau46, D. d'Enterria10, K. Das14, G. David5, F. Deák13, H. Delagrange46, A. Denisov17, A. Deshpande41, E. J. Desmond5, A. Devismes45, O. Dietzsch42, J. L. Drachenberg1, O. Drapier26, A. Drees45, A. Durum17, D. Dutta4, V. Dzhordzhadze47, Y. V. Efremenko36, H. En'yo40,41, B. Espagnon37, S. Esumi49, D. E. Fields34,41, C. Finck46, F. Fleuret26, S. L. Fokin24, B. D. Fox41, Z. Fraenkel52, J. E. Frantz10, A. Franz5, A. D. Frawley14, Y. Fukao25,40,41, S.-Y. Fung6, S. Gadrat29, M. Germain46, A. Glenn47, M. Gonin26, J. Gosset11, Y. Goto40,41, R. Granier de Cassagnac26, N. Grau19, S. V. Greene50, M. Grosse Perdekamp18,41, H.-Å. Gustafsson30, T. Hachiya16, J. S. Haggerty5, H. Hamagaki8, A. G. Hansen28, E. P. Hartouni27, M. Harvey5, K. Hasuko40, R. Hayano8, X. He15, M. Heffner27, T. K. Hemmick45, J. M. Heuser40, P. Hidas22, H. Hiejima18, J. C. Hill19, R. Hobbs34, W. Holzmann44, K. Homma16, B. Hong23, A. Hoover35, T. Horaguchi40,41,48, T. Ichihara40,41, V. V. Ikonnikov24, K. Imai25,40, M. Inaba49, M. Inuzuka8, D. Isenhower1, L. Isenhower1, M. Ishihara40, M. Issah44, A. Isupov20, B. V. Jacak45, J. Jia45, O. Jinnouchi40,41, B. M. Johnson5, S. C. Johnson27, K. S. Joo32, D. Jouan37, F. Kajihara8, S. Kametani8,51, N. Kamihara40,48, M. Kaneta41, J. H. Kang53, K. Katou51, T. Kawabata8, A. Kazantsev24, S. Kelly9,10, B. Khachaturov52, A. Khanzadeev39, J. Kikuchi51, D. J. Kim53, E. Kim43, G.-B. Kim26, H. J. Kim53, E. Kinney9, A. Kiss13, E. Kistenev5, A. Kiyomichi40, C. Klein-Boesing31, H. Kobayashi41, V. Kochetkov17, R. Kohara16, B. Komkov39, M. Konno49, D. Kotchetkov6, A. Kozlov52, P. J. Kroon5, C. H. Kuberg1, G. J. Kunde28, K. Kurita40, M. J. Kweon23, Y. Kwon53, G. S. Kyle35, R. Lacey44, J. G. Lajoie19, Y. Le Bornec37, A. Lebedev19,24, S. Leckey45, D. M. Lee28, M. J. Leitch28, M. A. L. Leite42, X. Li7, X. H. Li6, H. Lim43, A. Litvinenko20, M. X. Liu28, C. F. Maguire50, Y. I. Makdisi5, A. Malakhov20, V. I. Manko24, Y. Mao38,40, G. Martinez46, H. Masui49, F. Matathias45, T. Matsumoto8,51, M. C. McCain1, P. L. McGaughey28, Y. Miake49, T. E. Miller50, A. Milov45, S. Mioduszewski5, G. C. Mishra15, J. T. Mitchell5, A. K. Mohanty4, D. P. Morrison5, J. M. Moss28, D. Mukhopadhyay52, M. Muniruzzaman6, S. Nagamiya21, J. L. Nagle9,10, T. Nakamura16, J. Newby47, A. S. Nyanin24, J. Nystrand30, E. O'Brien5, C. A. Ogilvie19, H. Ohnishi40, I. D. Ojha3,50, H. Okada25,40, K. Okada40,41, A. Oskarsson30, I. Otterlund30, K. Oyama8, K. Ozawa8, D. Pal52, A. P. T. Palounek28, V. Pantuev45, V. Papavassiliou35, J. Park43, W. J. Park23, S. F. Pate35, H. Pei19, V. Penev20, J.-C. Peng18, H. Pereira11, V. Peresedov20, A. Pierson34, C. Pinkenburg5, R. P. Pisani5, M. L. Purschke5, A. K. Purwar45, J. Qualls1, J. Rak19, I. Ravinovich52, K. F. Read36,47, M. Reuter45, K. Reygers31, V. Riabov39, Y. Riabov39, G. Roche29, A. Romana26, M. Rosati19, S. Rosendahl30, P. Rosnet29, V. L. Rykov40, S. S. Ryu53, N. Saito25,40,41, T. Sakaguchi8,51, S. Sakai49, V. Samsonov39, L. Sanfratello34, R. Santo31, H. D. Sato25,40, S. Sato5,49, S. Sawada21, Y. Schutz46, V. Semenov17, R. Seto6, T. K. Shea5, I. Shein17, T.-A. Shibata40,48, K. Shigaki16, M. Shimomura49, A. Sickles45, C. L. Silva42, D. Silvermyr28, K. S. Sim23, A. Soldatov17, R. A. Soltz27, W. E. Sondheim28, S. Sorensen47, I. V. Sourikova5, F. Staley11, P. W. Stankus36, E. Stenlund30, M. Stepanov35, A. Ster22, S. P. Stoll5, T. Sugitate16, J. P. Sullivan28, S. Takagi49, E. M. Takagui42, A. Taketani40,41, K. H. Tanaka21, Y. Tanaka33, K. Tanida40, M. J. Tannenbaum5, A. Taranenko44, P. Tarján12, T. L. Thomas34, M. Togawa25,40, J. Tojo40, H. Torii25,41, R. S. Towell1, V-N. Tram26, I. Tserruya52, Y. Tsuchimoto16, H. Tydesjö30, N. Tyurin17, T. J. Uam32, H. W. van Hecke28, J. Velkovska5, M. Velkovsky45, V. Veszprémi12, A. A. Vinogradov24, M. A. Volkov24, E. Vznuzdaev39, X. R. Wang15, Y. Watanabe40,41, S. N. White5, N. Willis37, F. K. Wohn19, C. L. Woody5, W. Xie6, A. Yanovich17, S. Yokkaichi40,41, G. R. Young36, I. E. Yushmanov24, W. A. Zajc10,*, O. Zaudtke31, C. Zhang10, S. Zhou7, J. Zimányi22, L. Zolin20, and X. Zong19 (PHENIX Collaboration)
1Abilene Christian University, Abilene, Texas 79699, USA
2Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
3Department of Physics, Banaras Hindu University, Varanasi 221005, India
4Bhabha Atomic Research Centre, Bombay 400 085, India
5Brookhaven National Laboratory, Upton, New York 11973-5000, USA
6University of California–Riverside, Riverside, California 92521, USA
7China Institute of Atomic Energy (CIAE), Beijing, People's Republic of China
8Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
9University of Colorado, Boulder, Colorado 80309, USA
10Columbia University, New York, New York 10027, USA, and Nevis Laboratories, Irvington, New York 10533, USA
11Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France
12Debrecen University, H-4010 Debrecen, Egyetem tér 1, Hungary
13ELTE, Eötvös Loránd University, H-1117 Budapest, Pázmány P. s. 1/A, Hungary
14Florida State University, Tallahassee, Florida 32306, USA
15Georgia State University, Atlanta, Georgia 30303, USA
16Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
17Institute for High Energy Physics (IHEP), Protvino, Russia
18University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
19Iowa State University, Ames, Iowa 50011, USA
20Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia
21KEK, High Energy Accelerator Research Organization, Tsukuba-shi, Ibaraki-ken 305-0801, Japan
22KFKI Research Institute for Particle and Nuclear Physics (RMKI), H-1525 Budapest 114, POBox 49, Hungary
23Korea University, Seoul, 136-701, Korea
24Russian Research Center “Kurchatov Institute,” Moscow, Russia
25Kyoto University, Kyoto 606-8394, Japan
26Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France
27Lawrence Livermore National Laboratory, Livermore, California 94550, USA
28Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
29LPC, Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, France
30Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden
31Institut fuer Kernphysik, University of Muenster, D-48149 Muenster, Germany
32Myongji University, Yongin, Kyonggido 449-728, Korea
33Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan
34University of New Mexico, Albuquerque, New Mexico 87131, USA
35New Mexico State University, Las Cruces, New Mexico 88003, USA
36Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
37IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France
38Peking University, Beijing, People's Republic of China
39PNPI, Petersburg Nuclear Physics Institute, Gatchina, Russia
40RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan
41RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
42Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP05315-970, Brazil
43System Electronics Laboratory, Seoul National University, Seoul, South Korea
44Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA
45Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794, USA
46SUBATECH (Ecole des Mines de Nantes, CNRS-IN2P3, Université de Nantes), BP 20722-44307, Nantes, France
47University of Tennessee, Knoxville, Tennessee 37996, USA
48Department of Physics, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
49Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan
50Vanderbilt University, Nashville, Tennessee 37235, USA
51Waseda University, Advanced Research Institute for Science and Engineering, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan
52Weizmann Institute, Rehovot 76100, Israel
53Yonsei University, IPAP, Seoul 120-749, Korea
Received 21 April 2004; published 11 November 2004
We present a measurement of the double longitudinal spin asymmetry in inclusive π0 production in polarized proton-proton collisions at √s=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1–5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.
© 2004 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.93.202002
DOI:
10.1103/PhysRevLett.93.202002
PACS:
13.85.Ni, 13.88.+e, 21.10.Hw, 25.40.Fq
*PHENIX Spokesperson. Electronic address: zajc@nevis.columbia.edu
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