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Summary of Experimental Results

Jamie NagleUniversity of Colorado at Boulder

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OutlineOutlineWe have had an excellent workshop presenting a wealth of experimental results from RHIC and elsewhere.

My purpose here is not to re-present all the results shown at the workshop. Instead:

I hope to learn something by highlighting certain results and asking certain questions.

I hope you will learn something that you might have missed or not considered during the earlier presentations.

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Excellent TalksExcellent TalksT. Gunji (PHENIX)W. Dong (STAR)F. Kajihara (PHENIX)H. Zhang (STAR)E. Scomparin (SPS)J.-C. Peng (pA)R. Seuster (BELLE/OPAL)A. Geiser (HERA)M. Bishai (FNAL)T. Frawley (PHENIX)*J. Dunlop (STAR)*P. Crochet (LHC)*

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Heavy Quarks

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CERN Charm Enhancement?CERN Charm Enhancement?

Factor 3 Charm Enhancementin central Pb-Pb

M.C. Abreu et al., NA50, Eur. Phys. J C14(2000)443

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NA60 ResolutionNA60 Resolution

• Open charm and Drell-Yan generated with PYTHIA*• Drell-Yan normalization fixed using the high mass region• Open charm normalization using the world-average cc cross section

Clear excess in the IMR (1.2<m<2.7 GeV/c2) same order of magnitude as the NA50 result excess is not due to open charm enhancement the excess is due to a prompt source - which is still not known!

datapromptcharmprompt+charm

Excess World-aver. norm.

NA60 In+In 158 AGeV

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Total Charm Scaling at RHICTotal Charm Scaling at RHIC

S.S. Adler, et al., PRL 94 082301Binary scaling of total open charm yield

1.13 0.09(stat.) 0.42(sys.) mb in 200GeV minbias Au+Au collsions

1.4 0.2(stat.) 0.4(sys.) mb in 200GeV minbias d+Au collisions

Charm total cross section per NN interaction

Charm total cross section follows roughly Nbin scaling from d+Au to Au+Au considering errors

Indication of charm production in initial collisions

Quiz: What fraction of the charm cross section isrepresented by electrons above pT > 0.8 GeV?(a) 0.85, (b) 0.50, (c) 0.15

From the STAR data we know charm scales between 0.6 and 1.6 (but only for minimum bias AuAu). Thus, we should be cautious in our conclusions on scaling.

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What to Expect for Total Charm?What to Expect for Total Charm?

Extrapolating from lower energy is dangerous.Factor of 2 differences at RHIC, but large systematics.

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Charm/Beauty and pQCD NLOCharm/Beauty and pQCD NLO

Charm / Beauty in Photoproduction

Tevatron

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STAR BaselineSTAR Baseline

D and electron results complementary, but not possible to quote charm from electrons alone.

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Enormous pT Reach!Enormous pT Reach!

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PHENIX BaselinePHENIX BaselineProton-Proton Baseline Gold-Gold Suppression

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Suppression of High pSuppression of High pTT Charm Charm

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STAR Results - Moderate pTSTAR Results - Moderate pT

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Experimental ComparisonExperimental Comparison

"Suppression same as for light hadrons"RAA the same is not the same as the same energy loss.RAA agrees, but the proton-proton references are different by ~ 50% and so must the gold-gold !

-- at least at the time of QM2005 --

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Beauty Limits Suppression Factor?Beauty Limits Suppression Factor?

M. Djordjevic et al., nucl-th/0507019

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QuizQuizPlot shown by Wicks/Horowitz

What is the difference between these plots?1. alpha_s = 0.3 (left) and alpha_s = 0.4 (right)2. The STAR data shown at QM2005 and in their proceedings are different.

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New Direct ComparisonNew Direct Comparison

"STAR TOF, BEMC

and PHENIX agree

reasonably well.

Systematic

uncertainties are

under evaluation"

STAR high pT data

has decreased

significantly, and the

PHENIX results are

somewhat higher.

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***

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The three types of D mesons that contribute single electrons are:

name b.f. DeX percentage contribution to electrons in PYTHIAD+ 17.2% 21.6%D0 7.7% 66.8%D+

S 8.0% 11.6%

Note that most all excited charm mesons do not decay semi-leptonically, but only contribute via sequential decayD*+ D0 + 68.3%

D+ 0 30.6%D+ 1.1%

D*0 D0 0 61.9%D0 38.1%

D+/D0 = 0.32 (PYTHIA) gives an average b.f. DeX of 9.7%PHENIX paper uses D+/D0 = 0.65 0.35 which gives b.f. DeX of 11.0%Theory prediction of Lin, Vogt, Wang uses b.f. DeX of 12.0%

Possible Ds Measurement ?Possible Ds Measurement ?

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Heavy Quark

Anisotropy

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Non-Photonic Electron FlowNon-Photonic Electron Flow

PHENIX Preliminary

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Kinematics ReminderKinematics Reminder between D and electronpT electron between 0.25 GeV, 1.25 GeV, 2.25 GeVUsing FOCUS experiment simulation of decays.

Example D v2 and resulting electron v2...

Similar calculation for B v2 reveals electron v2 is always zero up to higher pT.

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STAR QM2005 ResultSTAR QM2005 Result

Not shown were "30-40%" systematic errors.

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STAR Workshop ReportSTAR Workshop Report

"The detector material in STAR caused too much photonic background, which caused huge systematic and statistical uncertainties. Our result is not sensitive enough to make any conclusion about heavy quark v2 so far. More work ahead!"

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Detailed TheoryDetailed TheoryIn a calculation by Teaney and Moore (hep-ph/0412346), they calculate the expected elliptic flow (v2) and transverse momentum modifications for different charm quark diffusion coefficients. The two effects go hand in hand.

My comment: Anything that increases the cross section for interactions will have this general effect.Does the specific resonance picture give something unique? Miklos' question on Form Factor.

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Theory ComparisonTheory Comparison

Theory curves from:Greco, Ko, Rapp: Phys. Lett. B595 (2004) 202

Note that v2 does not necessarily mean "flow"

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Heavy Quarkonia

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"Future of the History"..."Future of the History"...

What from the past is "solid" knowledge is oftennot so clear?

Must establish clearly what the facts are before a true theory can be developed and tested.

I think we are moving a long way in that direction!

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Heavy QuarkoniaHeavy Quarkonia

Color Screening

cc

Lattice QCD results show that the confining potential between heavy quarks is screened at high temperature.

This screening should suppress bound states such as J/.

However, recent lattice results indicate that the J/ spectral functions only show modest modification near the critical temperature, and thus may not be suppressed until higher T.

r

V(r

)/

Lattice QCD calculation

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Theorists Tell Us...Theorists Tell Us...

free energy : S.Digal et al. Phys.Rev.D64(2001)094015 linear comb. of both: C.Y.Wong hep-ph/0509088 internal energy: W.M.Alberico et al. hep-ph/0507084

J/ above Tc χc above Tc

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“Strong evidence for the formation of a transient quark-gluon phase without color confinement is provided by the observed suppression of the charmonium states J/, c, and ’.”

Maurice Jacob and Ulrich Heinz

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NA50 PublicationNA50 Publication

“A clear onset of the anomaly is observed. It excludes models based on hadronic scenarios since only smooth behavior with monotonic derivatives can be inferred from such calculations” Phys. Lett. B 450, 456 (1999).

Baseline is color octet c-c is absorbed by nucleons with = 6.2 mb

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D. Kharzeev, Nucl. Phys. A638, 279a (1998).

Invoking a model of bubble nucleation, one is able to reproduce the suppression. This implies a relatively strong 1st order phase transition. Or what about 2nd order with finite volume effects?

Resolving "Discontinuity" Is ImportantResolving "Discontinuity" Is Important

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Monotonic DerivativesMonotonic Derivatives

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What do we learn?What do we learn?Earlier papers from Satz et al. stated that nuclear absorption of 6 mb for octet state and 2 mb for singlet state.

Now the absorption cross section measured has changed from 6.2 mb to

abs)=4.18 +/- 0.35 mb (hep-ex/0412036)

Does that mean not all octet?Lack of reliability of calculation?Is this important for detailed balance calculations?

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NA60 DataNA60 Data

Quiz: What is the most central bin for which one can reliably quote Glauber parameters with "no systematic error"?(a) 20%, (b) 10%, (c) 5%, (d) 1%, (e) 0.1%

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Similar but no Discontinuity?Similar but no Discontinuity?

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New Heavy QuarkoniaNew Heavy Quarkonia

Note that most theories so far treat the topics of heavy quarks and heavy quarkonia quite separately, but they are intimately related.

Given the talks at this workshop, this lesson is something most theorists have accepted.

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proton-nucleus dataproton-nucleus dataUpsilon cross sections for p+d at 800 GeV

Open symbols: p + Cu (E605)Solid symbols: p + d (E866)

(2 ) / (1 ) and (3 ) / (1 ) ratios are A-independent S S S S

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Production MechanismsProduction Mechanisms

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T

L

T L

Transverse : ; helicity: 1;

Decay angular distribution in the qua

1

Longitudinal : ;

rkonium rest frame

helicity: 0; -1

Unpolarized : =2

1 cos

;

d

d

3 (1) 1 (8) 3 (8) 3 (8)1 0 1

2 (1 2 / ) / (1 2 / )

2

/ depends on the color - spin stat

helicity: 0, 1; 0

State:

es of the QQ pair :

Polarizatio

/ : 1/ 3.4 1/ 2 1/ 6 0

n o

/

1

f

T LL T

L T

L TT L

L T

JS S P S

QQ is sensitive to the production mechanism

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Tevatron ProductionTevatron Production

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J/J/ at HERA - NLO Singlet at HERA - NLO Singlet

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PolarizationPolarization

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PHENIX Deuteron-Gold DataPHENIX Deuteron-Gold Data

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Normal Nuclear + ShadowingNormal Nuclear + Shadowing

Forward rapidity

|y|<0.35 1.2<|y|<2.4

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Looks Like CERN SuppressionLooks Like CERN Suppression

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Quiz: Given an infinite number of predictions, what percentage of the time will some subset agree with the data?(a) 5%, (b) 20%, (c), 80%, (d) 100%Thus, we must find further discriminants!

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More in the Near Future...More in the Near Future...Copper-Copper 200 GeVJ/ |y| = 1.2-2.2

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Balancing EffectsBalancing Effects

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Rapidity DependenceRapidity Dependence

p+p

40-93%20-40%0-20%

Cu+Cu (200GeV)

p+p60-94%

40-60%

0-20%

20-40%

AuAu

CuCu

PHENIX Preliminary PHENIX Preliminary

nucl-th/0505055nucl-th/0507027

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Feed-Down - Key Measure!Feed-Down - Key Measure!

dirdirdirJJ SSSS '// 1.03.06.0

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Critical STAR ContributionCritical STAR Contribution0-80% Au+Au

STAR Preliminary

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Excellent Upgrade LessonsExcellent Upgrade Lessons

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Summary of the SummarySummary of the Summary

Great progress in utilizing heavy flavor for understanding heavy ion created medium.

Perhaps the start of also gaining more basic information such as production mechanics.

Final ExaminationWho should we thank?(a) all speakers(b) the organizers(c) RIKEN-BNL(d) Pam Esposito(e) All of the Above