Comprehensive study of heavy quark production by PHENIX at RHIC Youngil Kwon Univ. of Tennessee For the collaboration 21st Winter Workshop on Nuclear Dynamics Breckenridge, Colorado, 5-12 February, 2005

Feb. 10th, Y.Kwon for PHENIX2 Outline Physics Motivations RHIC & PHENIX Open heavy-flavor charm measurements –method –selected results for non-photonic e ± production from p+p collisions at √s = 200 GeV d+Au collisions at √s NN = 200 GeV as a function of centrality Summary & Outlook

Feb. 10th, Y.Kwon for PHENIX3 Physics Motivations Fundamental quest : Test prediction of the parton model and pQCD, and address limitations of them. Scenarios in discussion For the collisions of p + p collisions Is mass of charm quark heavy enough? Can pQCD be applied to charm production? J.C.Collins, D.E.Soper, G.Sterman, Nucl. Phys. B263, 37(1986) For the collisions of d+Au collisions Does “binary scaling” work? If charm producing process is point-like and there’s no modification of initial parton distribution, they will scale.

Feb. 10th, Y.Kwon for PHENIX4 J.C.Collins,D.E.Soper and G.Sterman, Nucl. Phys. B263, 37(1986) d  [A+B  X] =  ij f i/A  f j/B  d  [ij  cc+X]  D c  H +... Factorization f i/A,  f j/B : distribution function for point-like parton i,j D c  H : fragmentation function for c d  [ij  cc+X] : parton cross section +... : higher twist (power suppressed by  QCD /m c, or  QCD /p t if p t ≫ m c ) : e.g. "recombination" E.Braaten, Y.Jia, T. Mehen, PRL, (2002) Hard processes and factorization Process independent

Feb. 10th, Y.Kwon for PHENIX5 Application to nuclei f i/Au  79 f i/p f i/n  197 f i/N f i/d  f i/p + f i/n  2 f i/N Parton distribution for Au and d : d+Au Au+Au This scaling does not work for high pt particles in central Au+Au collisions! PHENIX, PRL, 91, (2003) For the interaction between point-like particles, Cross section  number of colliding nucleon pairs, Ex) 197 * 2 for the d+Au collisions!

Feb. 10th, Y.Kwon for PHENIX6 RHIC RHIC (Relativistic Heavy Ion Collider) –Dedicated to heavy ion physics & spin studies –4 experiments – GeV/A for various combinations of nuclei –p+p up to 500 GeV –Variable incident energy

Feb. 10th, Y.Kwon for PHENIX7 PHENIX Optimized for lepton measurements two central electron/photon/hadron spectrometers l electrons: central arms measurement range:  0.35 p  0.2 GeV/c two forward muon spectrometers l muons: forward arms muon measurement in range: 1.2 < |  | < 2.4 p  2 GeV/c

Feb. 10th, Y.Kwon for PHENIX8 BBC PHENIX, Detectors for centrality

Feb. 10th, Y.Kwon for PHENIX9 PHENIX, Acceptance for Particles

Feb. 10th, Y.Kwon for PHENIX10 measurement How to measure open charm and bottom Semi-leptonic decays contribute to single lepton spectra. Semileptonic decay Fragmentation

Feb. 10th, Y.Kwon for PHENIX11 e-measurement, Sources Charm decays Beauty decays Non-PHOTONIC Signal Photon conversions : Dalitz decays of  0, ,  ’, ,   0  ee ,   ee , etc) Kaon decays Conversion of direct photons Di-electron decays of , ,  Thermal di-leptons Most background is PHOTONIC Background  0   e+e-e+e-

Feb. 10th, Y.Kwon for PHENIX12 e-measurement, Signal Extraction (I) Mininum Bias Au+Au in  s NN =200GeV Inclusive e/photonic e NeNe 00 1.1% 1.7% Dalitz : 0.8% X 0 equivalent 0 With converter Conversion in converter W/O converter Conversion from detector 0.8% Non-photonic Non-photonic signal relative to photonic electrons depends on p T & collision system.

Feb. 10th, Y.Kwon for PHENIX13 excess above cocktail –increasing with p T –expected from charm decays attribute excess to semileptonic decays of open charm e-measurement, Signal Extraction (II) PHENIX: PRL 88(2002)  conversion  0   ee    ee, 3  0   ee,  0 ee   ee,  ee   ee  ’   ee

Feb. 10th, Y.Kwon for PHENIX14 1 : Hadrons, interacting and absorbed (98%), 3 : Hadrons, penetrating and interacting (“stopped”) 4 : Hadrons, “punch-through”, 2 : Charged   /K's, “decaying” before absorber (≤1%), 5 : Prompt muons, desired signal Tracker Identifier Absorber Collision range Collision Muon Hadron Absorber Symbols Detector 1  -measurement, Sources

Feb. 10th, Y.Kwon for PHENIX15  -measurement, Signal level 3 [arb. unit] An illustration of strength, Major background vs signal

Feb. 10th, Y.Kwon for PHENIX16  -measurement, Signal Extraction ( arb. Unit ) Generator 1. Hadron measurement. by central arm, 2. Extrapolation to muon arm acceptance. 3. Simplified spectrometer geometry.

Feb. 10th, Y.Kwon for PHENIX17 Inclusive e ±, p+p at √s = 200 GeV Following plots for p+p results from S. Butsyk’s dissertation.

Feb. 10th, Y.Kwon for PHENIX18 “Non-photonic” Electron Invariant Cross section from Converter Subtraction Good agreement between two independent methods

Feb. 10th, Y.Kwon for PHENIX19 Final “Non-photonic” Electron Invariant Cross section

Feb. 10th, Y.Kwon for PHENIX20 Comparison, PYTHIA PYTHIA parameters, tuned to describe the existing  s < 63 GeV p+N world data – PDF – CTEQ5L –m C = 1.25 GeV –m B = 4.1 GeV – = 1.5 GeV –K = 3.5 Total cross section from PYTHIA –  CC = mb –  BB = 3.77  b

Feb. 10th, Y.Kwon for PHENIX21 Comparison, FONLL Mateo Cacciari, private communication. FONLL : Fixed Order next-to-leading order terms and Next-to-Leading-Log large p T resummation. Central theory curve underpredict data by a factor of 2-3 when p T > 1.5 (GeV/c).

Feb. 10th, Y.Kwon for PHENIX22 non-photonic e ±, d+Au at √s NN = 200 GeV PHENIX PRELIMINARY 1/T AB EdN/dp 3 [mb GeV -2 ]

Feb. 10th, Y.Kwon for PHENIX23 Centrality & Glauber Model N BBC count N coll

Feb. 10th, Y.Kwon for PHENIX24 Centrality (in)dependence in d+Au collisions PHENIX PRELIMINARY 1/T AB 1/T AB EdN/dp 3 [mb GeV -2 ]

Feb. 10th, Y.Kwon for PHENIX25 Summary & Outlook Near future : –+ Single muons at forward rapidity. –+ Significant increase in statistics. Significant improvements in systematic and statistical uncertainty. PHENIX measured non-photonic electron production at mid-rapidity in p+p at √s = 200 GeV and d+Au at √s NN = 200 GeV. NLO pQCD underpredicts production in p+p when p T > 1.5 (GeV/c). This suggests limitation of pQCD-based approach for charm production. Observed “binary scaling” in d+Au is consistent with the point-like interaction for charm production. Improvements of error bars and measurement at the extended kinematic region, i.e. forward measurement, are highly desired.

Feb. 10th, Y.Kwon for PHENIX26 USA Abilene Christian University, Abilene, TX Brookhaven National Laboratory, Upton, NY University of California - Riverside, Riverside, CA University of Colorado, Boulder, CO Columbia University, Nevis Laboratories, Irvington, NY Florida State University, Tallahassee, FL Florida Technical University, Melbourne, FL Georgia State University, Atlanta, GA University of Illinois Urbana Champaign, Urbana-Champaign, IL Iowa State University and Ames Laboratory, Ames, IA Los Alamos National Laboratory, Los Alamos, NM Lawrence Livermore National Laboratory, Livermore, CA University of New Mexico, Albuquerque, NM New Mexico State University, Las Cruces, NM Dept. of Chemistry, Stony Brook Univ., Stony Brook, NY Dept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY Oak Ridge National Laboratory, Oak Ridge, TN University of Tennessee, Knoxville, TN Vanderbilt University, Nashville, TN Brazil University of São Paulo, São Paulo China Academia Sinica, Taipei, Taiwan China Institute of Atomic Energy, Beijing Peking University, Beijing France LPC, University de Clermont-Ferrand, Clermont-Ferrand Dapnia, CEA Saclay, Gif-sur-Yvette IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, Orsay LLR, Ecòle Polytechnique, CNRS-IN2P3, Palaiseau SUBATECH, Ecòle des Mines at Nantes, Nantes Germany University of Münster, Münster Hungary Central Research Institute for Physics (KFKI), Budapest Debrecen University, Debrecen Eötvös Loránd University (ELTE), Budapest India Banaras Hindu University, Banaras Bhabha Atomic Research Centre, Bombay Israel Weizmann Institute, Rehovot Japan Center for Nuclear Study, University of Tokyo, Tokyo Hiroshima University, Higashi-Hiroshima KEK, Institute for High Energy Physics, Tsukuba Kyoto University, Kyoto Nagasaki Institute of Applied Science, Nagasaki RIKEN, Institute for Physical and Chemical Research, Wako RIKEN-BNL Research Center, Upton, NY Rikkyo University, Tokyo, Japan Tokyo Institute of Technology, Tokyo University of Tsukuba, Tsukuba Waseda University, Tokyo S. Korea Cyclotron Application Laboratory, KAERI, Seoul Kangnung National University, Kangnung Korea University, Seoul Myong Ji University, Yongin City System Electronics Laboratory, Seoul Nat. University, Seoul Yonsei University, Seoul Russia Institute of High Energy Physics, Protovino Joint Institute for Nuclear Research, Dubna Kurchatov Institute, Moscow PNPI, St. Petersburg Nuclear Physics Institute, St. Petersburg St. Petersburg State Technical University, St. Petersburg Sweden Lund University, Lund *as of January Countries; 58 Institutions; 480 Participants*