1 Summary of Experimental Results Jamie Nagle University of Colorado at Boulder

2 Outline We 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.

3 Excellent Talks T. 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)*

4 Heavy Quarks

5 CERN Charm Enhancement? Factor 3 Charm Enhancement in central Pb-Pb M.C. Abreu et al., NA50, Eur. Phys. J C14(2000)443

6 NA60 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/c 2 )  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! data prompt charm prompt+charm Excess World-aver. norm. NA60 In+In 158 AGeV

7 Total Charm Scaling at RHIC S.S. Adler, et al., PRL Binary 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 is represented 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.

8 What to Expect for Total Charm? Extrapolating from lower energy is dangerous. Factor of 2 differences at RHIC, but large systematics.

9 Charm/Beauty and pQCD NLO Charm / Beauty in Photoproduction Tevatron

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

11 Enormous pT Reach!

12 PHENIX Baseline Proton-Proton BaselineGold-Gold Suppression

13 Suppression of High p T Charm

14 STAR Results - Moderate pT

15 Experimental Comparison "Suppression same as for light hadrons" RAA the same is not the same as the same energy loss. R AA agrees, but the proton-proton references are different by ~ 50% and so must the gold-gold ! -- at least at the time of QM

16 Beauty Limits Suppression Factor? M. Djordjevic et al., nucl-th/

17 Quiz Plot 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.

18 New 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.

19 ***

20 The three types of D mesons that contribute single electrons are: name b.f. D  eX percentage contribution to electrons in PYTHIA D %21.6% D 0 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 decay D* + D 0  % D +  % D +  1.1% D* 0 D 0  % D 0  38.1% D + /D 0 = 0.32 (PYTHIA) gives an average b.f. D  eX of 9.7% PHENIX paper uses D + /D 0 = 0.65  0.35 which gives b.f. D  eX of 11.0% Theory prediction of Lin, Vogt, Wang uses b.f. D  eX of 12.0% Possible Ds Measurement ?

21 Heavy Quark Anisotropy

22 Non-Photonic Electron Flow PHENIX Preliminary

23 Kinematics Reminder  between D and electron pT electron between 0.25 GeV, 1.25 GeV, 2.25 GeV Using 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.

24 STAR QM2005 Result Not shown were "30-40%" systematic errors.

25 STAR 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!"

26 Detailed Theory In a calculation by Teaney and Moore (hep-ph/ ), 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.

27 Theory Comparison Theory curves from: Greco, Ko, Rapp: Phys. Lett. B595 (2004) 202 Note that v2 does not necessarily mean "flow"

28 Heavy Quarkonia

29 "Future of the History"... What from the past is "solid" knowledge is often not 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!

30 Heavy Quarkonia 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

31 Theorists Tell Us... free energy : S.Digal et al. Phys.Rev.D64(2001) linear comb. of both: C.Y.Wong hep-ph/ internal energy: W.M.Alberico et al. hep-ph/ J/  above Tc χ c above Tc

32 “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

33 NA50 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

34 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 Important

35 Monotonic Derivatives

36 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 +/ mb (hep-ex/ ) Does that mean not all octet? Lack of reliability of calculation? Is this important for detailed balance calculations?

37 NA60 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%

38 Similar but no Discontinuity?

39 New 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.

40 proton-nucleus data Upsilon cross sections for p+d at 800 GeV Open symbols: p + Cu (E605) Solid symbols: p + d (E866)

41 Production Mechanisms

42 Tevatron Production

43 J/  at HERA - NLO Singlet

44 Polarization

45 PHENIX Deuteron-Gold Data

46 Normal Nuclear + Shadowing Forward rapidity |y|< <|y|<2.4

47 Looks Like CERN Suppression

48

49 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!

50 More in the Near Future... Copper-Copper 200 GeV J/  |y| =

51 Balancing Effects

52 Rapidity Dependence p+p 40-93% 20-40% 0-20% Cu+Cu (200GeV) p+p 60-94% 40-60% 0-20% 20-40% AuAu CuCu PHENIX Preliminary nucl-th/ nucl-th/

53 Feed-Down - Key Measure!

54 Critical STAR Contribution 0-80% Au+Au STAR Preliminary

55 Excellent Upgrade Lessons

56 Summary 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 Examination Who should we thank? (a) all speakers (b) the organizers (c) RIKEN-BNL (d) Pam Esposito (e) All of the Above