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Hangzhou Workshop 2006

Hangzhou Workshop 2006. Closing comments with a historical perspective. Rudolph C. Hwa University of Oregon. Workshop on Correlation and Fluctuation in Multiparticle Production Hangzhou, China November 21-24, 2006. 1986. Aspen workshop was not really a part of the series:

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Hangzhou Workshop 2006

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  1. Hangzhou Workshop 2006

  2. Closing comments with a historical perspective Rudolph C. Hwa University of Oregon Workshop on Correlation and Fluctuation in Multiparticle Production Hangzhou, China November 21-24, 2006

  3. 1986

  4. Aspen workshop was not really a part of the series: • not openly announced • very few participants selected by P. Carruthers • 1 seminar a day for 2 weeks • no proceedings Pete wanted it to be included in the listing of the series.

  5. Shandong Workshop at Jinan in 1987 was first in the series in the present format. Organized by Q.B. Xie and R. Hwa Discussion time was almost as much as for formal presentations. Interruptions allowed. “Multiparticle production is regarded by particle physicists as being too complicated and therefore declared uninteresting. “The malaise is basically an internal one. The absence of a workable theory gave rise to a proliferation of models, many of which bear little resemblance to one another. …. The field not only has no first principles to rely on,… it has generated no collective wisdom to serve as a guide to the construction of models.” In the International Conference on High Energy Physics (Berkeley, 1986) there was not one session devoted exclusively to soft hadronic processes and multiparticle production. The need for a workshop was obvious.

  6. W. Kittel L. Van Hove B. Andersson X.N.Wang A. Capella Q.B.Xie Y.F.Wu W. Zajc

  7. Exp Th Jinan (40) 4 28 9 days Hangzhou (48) 19 18 4 days Experimental reports: NA22, NA9 (EMC) & WA21 UA1 UA5 Theoretical reports: 28 (only one talk on each model)

  8. LUND MC

  9. No dynamics C N

  10. Reaffirmed byexperiments at RHIC

  11. Multiplicity density measurements in PHENIX Δη<0.7 integrated over Δφ<π/2 PHENIX: Au+Au √sNN=200GeV Probability (A.U.) PHENIX Preliminary small dh large dh Zero magnetic field to enhance low pt statistics per collision event n/<n> Negative Binomial Distribution can describe data very well. Kensuke Homma (PHENIX) July 3, 2006 inFlorence (Italy) at the Galileo Galilei Institute

  12. Intermittency Jets BE correlation always discussed in big meetings Critical fluctuations Experimental reports LEP SPS RHIC Nijmegen 96 Matrahaza 98 Torino 00 Crete 02 Hangzhou 06 5 8 0 5 5 0 6 5 0 5 1 3 1 0 18 Only a small sample of mountains of data from RHIC Jinan 87 Perugia 88 Santa Fe 90 Ringberg 91 Cracow 93 Nijmegen 96 Matrahaza 98 Torino 00 Crete 02 Hangzhou 06 Fluctuations and fractal structure Physics is driven by experiments

  13. 100 10 1 10 103 102 104 The medium effect complicates the interpretation problem Nuclear Complex systems A After jets became well understood, they have been used as probes Jetsand multiplicity distributions Hadronic √s Leptonic Partons and jets Multiplicity distributions Pn: In pp collisions, it was thought to give clues to the dynamics of particle production (Negative Binomial) In AA collisions, NB still works, but hydrodynamics reproduces soft particle spectra well.

  14. All other spectra at other centralities and species are well reproduced. Do calculation in Relativistic Hydrodynamics Initial condition and final freeze-out put in by hand to solve hydro eq Kolb & Heinz, QGP3 equ=0.6 fm/c Tinit=340 MeV init=25 GeV/fm3Tdec=130 MeV

  15. The question is not whether we have found QGP, but what its properties are. Do calculation in Relativistic Hydrodynamics Initial condition and final freeze-out put in by hand to solve hydro eq Kolb & Heinz, QGP3 equ=0.6 fm/c Tinit=340 MeV init=25 GeV/fm3Tdec=130 MeV All other spectra at other centralities and species are well reproduced.

  16. We have three topics at this Workshop: BE correlation Event-by-event fluctuation Correlation in jets In order to connect the three topics we need a metaphor.

  17. treacherousdemonic --slayer is courageous good fortune, power, wisdom longevity Siegfried killed the dragon with Nothung, tasted the blood of the dragon, and gained knowledge Let dragon be the metaphor for QGP.

  18. good fortune, power, wisdom longevity • First, we have to find the dragon. We have to recognize the beast that we are searching for. BE correlation: space-time properties  correlation of momentum variables A description of the beast as seen from the outside, far away. The “HBT puzzle” has ruled out many models. Survivers: AMPT, hadronic cascade, Buda-Lund, Cracow, Blast-wave, Renk, granular QGP,… The power of HBT to constrain the description of space-time evolution.

  19. T. Renk, PRC (04) Zhang, Ren, Wong, PRC (06) Very different evolutionary systems. Either improve the analyses (Danielewicz, Enokizono, Eggers, Mrowczynski) or consider some other more penetrating probes Not enough interaction between theory and exp’t at this workshop.

  20. halo? treacherousdemonic --slayer is courageous • Next, the slaying of the dragon. If the birth and death of the dragon is not a figment of our imagination, then we can ask: Is the birth-death transition a phase transition of the first or second order? Event-by-event fluctuation  properties critical behavior (We have to create many dragons and then kill them one by one) By the way in which the dragons die, we are supposed to learn about the nature of the mythological beast.

  21. What can we learn from fluctuations? Gunther Roland (How) Does matter thermalize? Nature of the phase transition? Properties of the medium? How are hadrons made? How is entropy produced? Unique answers to all of these questions from fluctuations/correlations How far have we come trying to realize this promise?

  22. Summary by Tapan Nayak Detailed EbyE physics and fluctuation to understand the physics of bulk matter as well as high-pT particles and jets. EbyE addresses many diversified topics – • Temperature fluctuation • <pT> fluctuations • Multiplicity fluctuations • Net charge fluctuation • Moments of net charge • Baryon-strangeness correlation • HBT correlations: EbyE • Resonances measured EbyE and fluctuation • EbyE Flow , fluctuation in v2 • Disoriented chiral condensates • Long range correlations • Fluctuations in the presence of jets Would be interesting to isolate events of interest and study those in detail.

  23. Universal Scaling: pT-independent  is supposed to diverge at the critical point. small !? small !? scaled variance compressibility correlation length 0.2 < pT < 0.75 GeV/c 0.2 < pT < 0.75 GeV/c J. Mitchell, QM06

  24. So far we have not gained much understanding about the critical behavior from the study of fluctuations. Stanislaw Mrowczynski has a more optimistic view: we have learned something about hadronization at the end of the time evolution. The problem: critical exponents, etc., are for static systems. But QGP is an evolving system with T depending on spatial coordinates and time.

  25. pions emitted first pions emitted later T r Since all hadrons in each event go to the detector, they are superimposed. Correlations that exist at the same time of emission are different from those at different times. How can the effects be disentangled? E-by-e fluctuations take the whole event as a package. One studies the fluctuation from dragon to dragon. But different parts of the dragon die at different times.

  26. Finally, what is the biological structure of the dragon? (Since we have never found any archeological remains of the mythological beast, they must vanish after being slain, like Obi-Wan Kenobi.) MRI, while alive, would be useful. Jet tomography Correlations in pT, ,  in 1-jet or between back-to-back jets The most intense interaction between exp’t and theory is in jet correlations Exp’t 9, theory 8 Near and far sides probe different properties of the medium, since trigger-bias favors the jet to originate near the surface.

  27. Not like a resonance jet+ridge    + jet ridge  ridge jet trigger partners If pt(assoc) is too low, we have more ridge than jet. Jet structure is complicated, even on the near side. width height Ridge is stimulated by the hard parton, and is a part of the JET. The whole picture is likely to change at LHC.

  28. Siegfried killed the dragon with Nothung, tasted the blood of the dragon, and gained knowledge. On the far side one can learn more about the medium What happens when Nothung pierces the dragon? -- jet quenching Is the blood of dragon thick or thin? -- energy loss How does the dragon react? -- Mach cone, deflected jet

  29. 2 1 Mach cone deflected jet Much attention has been given to Mach cone  3-particle correlation Mach cone effect shock wave in medium  speed of sound in plasma What is the difference between the two?

  30. F. Wang, Ponta Delgada, 2006 Even though the Mach cone effect is weaker, its presence implies collective medium response to the passage of a parton. What is the speed of sound? It seems to be too low. What is the nature of the “shock wave” at forward rapidity? The dominant effect seems to be due to deflected jets -- at midrapidity and forward region.

  31. BE correlation: testing ground of new methods proposed. Event-by-event fluctuations: a lot more particles will be produced with a lot of fluctuations. Correlations in jets: There will be a lot more jets at LHC. Looking ahead toward LHC, the dragon will be larger. We don’t even know whether it will be sQGP or wQGP. • The large number of jets will alter conventional low pt physics, since jets will generate soft partons. • BE correlation and e-by-e fluctuation will be affected. • Background consists of many jets, so subtraction will not be done by use of v2. Expect new methods and unanticipated results.

  32. Dragons in different cultures Chinese emperors averaged over all evts all St. George all particles study fluctuations Siegfried large trigger various associated averaged over all triggered events Experimental Arenas BE correlation E-by-E fluctuation Correlation in jets

  33. BE correlation Temporal evolution Ro ,Rs ,Rl E-E fluctuation collective Space-time behavior Hadronization Mach, Ring local Correlation in jets Theoretical overview Size and shape of system Critical behavior of phase transition Properties of dense medium

  34. let us appreciate what we have had in the last four days, and give While we look forward to another Workshop on Correlations and Fluctuations in the future,

  35. HANGZHOU WORKSHOP2006 THANKS to the ORGANIZERS for this successful and enjoyable

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