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Fukutaro Kajihara(CNS, University of Tokyo)

for the PHENIX Collaboration

Heavy Quark Measurement by Single Electrons

in the PHENIX Experiment

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0

Dir.

IntroductionVery large suppression

and v2 have been observed for light quarks and gluons at RHIC

Parton energy loss and hydrodynamics explain them successfully

Next challenge: light heavy quark (HQ: charm and bottom)HQ has large massHQ has larger thermalization time than light quarksHQ is produced at the very early timeHQ is not ultra-relativistic ( v < 4 ) HQ will help systematic understanding of medium property at RHIC

Experimental approach:Electrons from semi-leptonic heavy flavor decays in mid rapidity (||<0.35)

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Motivations in p+p at s = 200 GeV

HQ Production MechanismDue to large mass, HQ

productions are considered as point-like pQCD processes

HQ is produced at the initialvia leading gluon fusion, and sensitive to the gluon PDF

FONLL pQCD calculation describes our single electronresults in Run-2 and Run-3 within theoretical uncertainties

Important ReferencesRAA calculation of HQImportant input for J/ studies

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Motivations in Au+Au at sNN = 200 GeV

G.D. Moore, D Teaney PR. C71, 064904 (2005)

Energy loss and flow are related to the transport properties of the medium in HIC: Diffusion constant (D)

Moreover, D is related to viscosity/entropy density ratio (/s) which ratio could be very useful to know the perfect fluidity

HQ RAA and v2 (in Shingo’s talk) can be used to determine D

sTD

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Data Analysis

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Electron Signal and Background

Conversion of photons in material Main photon source: → In material: → e+e- (Major contribution of photonic electron)

Dalitz decay of light neutral mesons→ e+e- (Large contribution of photonic)

The other Dalitz decays are small contributions Direct Photon (is estimated as very small contribution)

Heavy flavor electrons (the most of all non-photonic) Weak Kaon decays

Ke3: K± → e± e (< 3% of non-photonic in pT > 1.0 GeV/c) Vector Meson Decays

J → e+e-(< 2-3% of non-photonic in all pT.)

[Photonic electron] … Background

[Non-photonic electron] … Signal and minor background

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Most sources of backgroundhave been measured in PHENIX

Decay kinematics and photon conversions can be reconstructed by detector simulation

Then, subtract “cocktail” of all background electrons from the inclusive spectrum

Advantage is small statistical error.

Background Subtraction: Cocktail Method

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Background Subtraction: Converter Method

We know precise radiation length (X0) of each detector material

The photonic electron yield can be measured by increase of

additional material (photon converter was installed)

Advantage is small systematic error in low pT region

Background in non-photonic issubtracted by cocktail method

Photon Converter (Brass: 1.7% X0)

Ne Electron yield

Material amounts:

0

0.4% 1.7%

Dalitz : 0.8% X0 equivalent radiation length

0

With converter

W/O converter

0.8%

Non-photonic

Photonic

converter

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Consistency Check of Two MethodsAccepted by PRL (hep-ex/0609010)

Accepted by PRL (hep-ex/0609010)

Both methods were always checked each other

Ex. Run-5 p+p in left

Left top figure shows Converter/Cocktail ratio of photonic electrons

Left bottom figure shows non-photon/photonic ratio

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New Results are Available!!

Run-5 p+p result at s = 200 GeV

Run-4 Au+Au result at sNN = 200 GeVImprovements over QM05:

Higher statistics and smaller systematic error

pT range is extended: 0.3<pT<9.0 GeV/c Both cocktail and converter methodsNonphotonic/Photonic ratio updates v2 calculation (in Shingo’s talk)

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Run-5 p+p Result at s = 200 GeV

Heavy flavor electroncompared to FONLL

Data/FONLL = 1.71 +/- 0.019 (stat) +/- 0.18 (sys)

FONLL agrees with datawithin errors

All Run-2, 3, 5 p+p data areconsistent within errors

Total cross section of charmproduction: 567 b+/- 57 (stat) +/- 224 (sys)

Accepted by PRL (hep-ex/0609010)

Upper limit of FONLL

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Run-4 Au+Au Result at sNN = 200 GeV

Heavy flavor electroncompared to binary scaledp+p data (FONLL*1.71)

Clear high pT suppression in central collisions

S/B > 1 for pT > 2 GeV/c

(according to inside figure)

Submitted to PRL (nucl-ex/0611018)

MB

p+p

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Nuclear Modification Factor: RAA

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33

dpdT

dPNdpR

ppAA

AATAA

p+p reference:

Data (converter) for pT<1.6 [GeV/c]

1.71*FONLL for pT>1.6 [GeV/c]

Suppression level is the almost same as 0 and in high pT region

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Integrated RAA vs. Npart

ppAA

AApartAA T

NNR

Binary scaling works

well for pT>0.3 GeV/c integration (about 50% of total charm yield)

Clear suppression is seen for pT>3.0 GeV/c integration

Suppression of D meson is probably less than 0

Submitted to PRL (nucl-ex/0611018)

Total error from p+p

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Comparisons with Theories

Submitted to PRL (nucl-ex/0611018)

(I) pQCD calculation with radiative energy loss Large parton densities and strong coupling ( ~ 14 GeV2/fm) Light hadron suppression is also described with the same value

q̂

Anyway, charm/bottom identification is needed for more development

See combined RAA and v2

discussion in Shingo’s talk

0-10 % centrality

(II) (III) include elastic collision mechanism of HQ Their models provide diffusion constant D (2T*D=4-6 in (II))

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Summaryp+p collisions at s=200 GeV in mid rapidity

　 New measurement of heavy flavor electrons for 0.3 < pT < 9.0 GeV/c

　　 FONLL describes the measured spectrum within systematic error (Data/FONLL = 1.7)

Au+Au collisions at s=200 GeV in mid rapidity 　 Heavy flavor electrons are measured for 0.3 < pT < 9.0 GeV/c

Binary scaling of integrated charm yield (pT > 0.3 GeV/c) works well

RAA shows a strong suppression for high pT region

ه OutlookD meson measurement in p+p by electron and K measurement

High statistic Cu+Cu analysisSingle measurement in forward rapidityD/B direct measurement by Silicon Vertex Tracker

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University of São Paulo, São Paulo, Brazil Academia Sinica, Taipei 11529, China China Institute of Atomic Energy (CIAE), Beijing, P. R. China Peking University, Beijing, P. R. China Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 12116

Prague, Czech Republic Czech Technical University, Faculty of Nuclear Sciences and Physical

Engineering, Brehova 7, 11519 Prague, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na

Slovance 2, 182 21 Prague, Czech Republic Laboratoire de Physique Corpusculaire (LPC), Universite de Clermont-

Ferrand, 63 170 Aubiere, Clermont-Ferrand, France Dapnia, CEA Saclay, Bat. 703, F-91191 Gif-sur-Yvette, France IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406 Orsay, France Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de

Saclay, F-91128 Palaiseau, France SUBATECH, Ecòle des Mines at Nantes, F-44307 Nantes France University of Muenster, Muenster, Germany KFKI Research Institute for Particle and Nuclear Physics at the Hungarian

Academy of Sciences (MTA KFKI RMKI), Budapest, Hungary Debrecen University, Debrecen, Hungary Eövös Loránd University (ELTE), Budapest, Hungary Banaras Hindu University, Banaras, India Bhabha Atomic Research Centre (BARC), Bombay, India Weizmann Institute, Rehovot, 76100, Israel Center for Nuclear Study (CNS-Tokyo), University of Tokyo, Tanashi, Tokyo

188, Japan Hiroshima University, Higashi-Hiroshima 739, Japan KEK - High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba,

Ibaraki 305-0801, Japan Kyoto University, Kyoto, Japan Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-

0198, Japan RIKEN – BNL Research Center, Japan, located at BNL Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima,

Tokyo 171-8501, Japan Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi Ibaraki-ken 305-8577,

Japan Waseda University, Tokyo, Japan Cyclotron Application Laboratory, KAERI, Seoul, South Korea Kangnung National University, Kangnung 210-702, South Korea Korea University, Seoul, 136-701, Korea Myong Ji University, Yongin City 449-728, Korea System Electronics Laboratory, Seoul National University, Seoul, South

Korea Yonsei University, Seoul 120-749, Korea IHEP (Protvino), State Research Center of Russian Federation "Institute for

High Energy Physics", Protvino 142281, Russia Joint Institute for Nuclear Research (JINR-Dubna), Dubna, Russia Kurchatov Institute, Moscow, Russia PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region,

188300, Russia Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State

University, Vorob'evy Gory, Moscow 119992, Russia Saint-Petersburg State Polytechnical Univiversity, Politechnicheskayastr, 29,

St. Petersburg, 195251, Russia

Lund University, Lund, Sweden Abilene Christian University, Abilene, Texas, USA Brookhaven National Laboratory (BNL), Upton, NY 11973, USA University of California - Riverside (UCR), Riverside, CA 92521, USA University of Colorado, Boulder, CO, USA Columbia University, Nevis Laboratories, Irvington, NY 10533, USA Florida Institute of Technology, Melbourne, FL 32901, USA Florida State University (FSU), Tallahassee, FL 32306, USA Georgia State University (GSU), Atlanta, GA, 30303, USA University of Illinois Urbana-Champaign, Urbana-Champaign, IL, USA Iowa State University (ISU) and Ames Laboratory, Ames, IA 50011, USA Los Alamos National Laboratory (LANL), Los Alamos, NM 87545, USA Lawrence Livermore National Laboratory (LLNL), Livermore, CA 94550, USA University of New Mexico, Albuquerque, New Mexico, USA New Mexico State University, Las Cruces, New Mexico, USA Department of Chemistry, State University of New York at Stony Brook (USB),

Stony Brook, NY 11794, USA Department of Physics and Astronomy, State University of New York at Stony

Brook (USB), Stony Brook, NY 11794, USA Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA University of Tennessee (UT), Knoxville, TN 37996, USA Vanderbilt University, Nashville, TN 37235, USA

Map No. 3933 Rev. 2 UNITED N ATIONSAugust 1999

Department of Public InformationCartographic Section

13 Countries; 62 Institutions; 550 Participants*

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Backup slides