14 Sep 2012
University of Illinois at Urbana-ChampaignNational Central UniversityVanderbilt UniversityKorea UniversitySungkyunkwan University
Kyoto University
University of MichiganYonsei University
RIKEN
Texas A&M UniversityJoint Institute for Nuclear Research
Yale UniversityLouisiana State University
Columbia University
University of PennsylvaniaWeizmann Institute of ScienceFlorida State University
University of Maryland
University of Tokyo
Seoul National University
Brookhaven National Laboratory
Rutgers UniversityUniversity of Colorado
Lawrence Berkeley National LaboratoryLos Alamos National LaboratoryOak Ridge National LaboratoryIowa State UniversityHiroshima UniversityUniversity of TennesseeUniversity of TsukubaOregon State UniversityGeorgia State UniversityState University of New York at Stony BrookUniversity of MassachusettsNihon UniversityNew Mexico State UniversityBhabha Atomic Research CentreUniversity of California RiversideBanaras Hindu UniversityUniversidade de Sao PauloChina Institute of Atomic EnergyNational Research Nuclear University MEPhI (Moscow Engineering Physics Institute)Czech Technical UniversityIHEPAbilene Christian UniversityRIKEN BNL Research CenterInstitute for Nuclear Theory, University of WashingtonKEK (High Energy Accelerator Research Organization)Nara Women’s UniversityCharles University, Faculty of Mathematics and PhysicsMyongji UniversityNagasaki Institute of Applied ScienceMuhlenberg CollegeWigner Research Centre for Physics, Hungarian Academy of SciencesPhilipps-Universit¨at Marburg20 Joint Institute for Nuclear Research, Dubna, 141980, Russia46 Universidade de S˜ao Paulo, S˜ao Paulo, SP, 05389-970, Brazil19 Centre de Recherches Subatomiques de Strasbourg, Universit´e Louis Pasteur, F-67037 Strasbourg, France26 Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA33 Nara Women's University, Kita-uoya-nishi, Nara 630-8506, Japan37 State University of New York at Stony Brook, Stony Brook, New York 11794, USA31 Myongji University, Yongin, Kyonggido 449-728, Korea52 University of Tsukuba, Tsukuba, Ibaraki 305, Japan56 Yale University, New Haven, Connecticut 06520, USA9 China Institute of Atomic Energy, Beijing 102413, P.R. China12 Dauer University, Dauer, 34567, Dauer, Czech Republic57 Yonsei University, Seoul 120-749, Korea39 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6379, USA42 Philipps-Universit¨at Marburg, 35032 Marburg, Germany30 Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA44 RIKEN, Wako, Saitama 351-0198, Japan34 National Central University, Chung-li 32054, Taiwan21 KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan14 Georgia State University, Atlanta, Georgia 30303, USA18 Iowa State University, Ames, Iowa 50011, USA11 Czech Technical University, Prague, 128 00 Prague, Czech Republic27 Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742, USA55 Wigner Research Centre for Physics, Hungarian Academy of Sciences, POBox 49, 1525 Budapest, HungaryCEA, Irfu, SPN, Centre de Saclay47 CEA, Irfu, SPN, Centre de Saclay, F-91191 Gif-sur-Yvette, France5 Brookhaven National Laboratory, Upton, New York 11973-5000, USA49 Sungkyunkwan University, Suwon 440-746, Korea2 Center for Nuclear Study, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan25 Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA6 University of California-Riverside, Riverside, California 92521, USA10 Columbia University, New York, New York 10027, USA22 Korea University, Seoul 136-701, Republic of Korea54 Weizmann Institute of Science, Rehovot 76100, Israel24 Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA58 Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195, USA53 Vanderbilt University, Nashville, Tennessee 37235, USA7 University of Colorado, Boulder, Colorado 80309, USADauer University32 Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, Japan35 National Research Nuclear University MEPHI (Moscow Engineering Physics Institute), Moscow 115409, Russia13 Florida State University, Tallahassee, Florida 32306, USA29 University of Michigan, Ann Arbor, Michigan 48109-1120, USA15 Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan40 Oregon State University, Corvallis, Oregon 97331, USA50 University of Tennessee, Knoxville, Tennessee 37996, USA43 RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA4 Department of Physics, Banaras Hindu University, Varanasi 221005, India23 Kyoto University, Kyoto 606-8502, JapanCentre de Recherches Subatomiques de Strasbourg, Universit´e Louis Pasteur28 Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA38 Nihon University, Chiyoda, Tokyo 101-8308, Japan45 Rutgers University, Piscataway, New Jersey 08854-8071, USA16 IHEP, Protvino, Moscow Region, 142281, Russia36 New Mexico State University, Las Cruces, New Mexico 88003, USA51 Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA17 University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA41 University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA48 Seoul National University, Seoul 151-742, Korea8 Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague, Czech Republic1. Abilene Christian University, Abilene, Texas 79699, USA3. Bhabha Atomic Research Centre, Bombay 400 085, IndiaThe energy dependence of the single-transverse-spin asymmetry, A_N, and the cross section for neutron production at very forward angles were measured in the PHENIX experiment at RHIC for polarized p+p collisions at sqrt(s)=200 GeV. The neutrons were observed in forward detectors covering an angular range of up to 2.2 mrad. We report results for neutrons with momentum fraction of x_F=0.45 to 1.0. The energy dependence of the measured cross sections were consistent with x_F scaling, compared to measurements by an ISR experiment which measured neutron production in unpolarized p+p collisions at sqrt(s)=30.6--62.7 GeV. The cross sections for large x_F neutron production for p+p collisions, as well as those in e+p collisions measured at HERA, are described by a pion exchange mechanism. The observed forward neutron asymmetries were large, reaching A_N=-0.08+/-0.02 for x_F=0.8; the measured backward asymmetries, for negative x_F, were consistent with zero. The observed asymmetry for forward neutron production is discussed within the pion exchange framework, with interference between the spin-flip amplitude due to the pion exchange and nonflip amplitudes from all Reggeon exchanges. Within the pion exchange description, the measured neutron asymmetry is sensitive to the contribution of other Reggeon exchanges even for small amplitudes.
There are no more papers matching your filters at the moment.
