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Collective flow

Collective flow. Fabrice Reti è re Lawrence Berkeley National Laboratory. Flow (in the transverse plane) A mid-peripheral collision. Flow. Y. Out-of-plane. In-plane. Reaction plane. Flow. X. Dashed lines: hard sphere radii of nuclei. Re-interactions  FLOW

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Collective flow

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  1. Collective flow Fabrice Retière Lawrence Berkeley National Laboratory

  2. Flow(in the transverse plane)A mid-peripheral collision Flow Y Out-of-plane In-plane Reaction plane Flow X Dashed lines: hard sphere radii of nuclei Re-interactions  FLOW Re-interactions among what? Hadrons, partons or both? In other words, what equation of state?

  3. Outline • Recent data on anisotropic flow • v1, v2, v4 and non-flow issues • Coping with a wealth of data self-consistently and quantitatively • What flow? partonic or hadronic, or both? • Summary

  4. Anisotropic flow, v1, v2, v4, … h~3 h~-3 h~0 Reaction plane Spectators Spectators Y v2 = 15% v2 = 15%, v4=4% 1.5 1 Out-of-plane 0.5 In-plane X v2 = 7% v2 = 7%, v1=+7% v2 = 7% v2 = 7%, v1=-7% Isotropic emission

  5. Directed flow v1 v2 is positive, i.e. v1 and v2 are in the same plane STAR STAR, nucl-ex/0310029 NA49, Phys. Rev. C 69 (2003) 034903 Talks by M. Belt-Tonjes (PHOBOS), A.Tang (STAR) Posters by H. Masui (PHENIX), M. Oldenburg (STAR) h PHENIX preliminary Poster by Hiroshi Masui

  6. v2 vs rapidity at RHIC STAR preliminary PHOBOS QM02 This afternoon’s talk by M.B. Tonjes’s (PHOBOS) and U.Heinz (theory) M.Oldenburg’s poster (STAR)

  7. Higher harmonics v4 and v6 STAR, Au-Au √s=200 GeV Talk by A. Poskanzer • New constraints to models • Hydro* does not get v2 and v4 simultaneously • v2 scaled by 0.55 to match data • Blast wave • Parameters fixed to fit v2 • requires a 4th order parameters (see A. Poskanzer’s talk) *P.Kolb Phys.Rev. C68 (2003) 031902

  8. Non-flow issues STAR preliminary, √s=200 GeV • v2 • Scalar products(1) • Sensitive to both flow and non-flow • Df correlation • Disentangle jets from flow • Lee-Yang zeroes(2) and high order cumulants • Cumulants even from PHENIX(3) • A. Tang’s talk • N. Borghini’s talk • M. Issah’s poster p-p is the non-flow baseline

  9. Spectra Different energy AGS energies SPS: 20, 30 40, 80, 60 RHIC: 19.6, 130, 200 Many particle species, e.g. X, W, f Charm Many centralities Different rapidities Two-particle correlations Source size (HBT) Different energy Different centrality Different rapidity Kaons Wrt reaction plane Source shift (Non-id correlation) Tuesday’s talk by A.Kisiel Including p-X correlation! Other data sensitive to flow are also becoming available

  10. Understanding flow • Requires to describe the data (spectra, anisotropic flow, two-particle correlations): • Self-consistently • Quantitatively • And understand the evolution of the system • No definite conclusions can be made with only freeze-out parameterizations

  11. Understanding flow: models • Hadronic cascades (RQMD, uRQMD, …) • Do well at SPS, except too long source size • Flow too weak at RHIC • Partonic cascades (MPC, AMPT, …) • Do a reasonable job at RHIC with huge partonic x-sections • Hydro • Do well for spectra and v2 • Do not reproduce source size and lifetime (from HBT) See for details: - Following talk by T.Hirano - This afternoon’s talks by S.Bass, U.Heinz, D. Molnar, E.Shuryak, D.Teaney

  12. Self-consistent Quantitative characterization of the freeze-out stage On the market “Krakow” single freeze-out* BudaLund** Blast Wave Do not describe the system evolution Understanding flow: parameterizations *Friday’s talk by W.Florkowski W.Broniowski et al., nucl-th/0212052, nucl-th/0212053, … ** tuedsay’s talk and poster by M.Csanad M. Csanád, T. Csörgő, B. Lörstad and A. Ster,nucl-th/0311102 and nucl-th/0310040, … Snapshot of the freeze-out stage

  13. Blast-wave Spectra T=106 ± 1 MeV <bInPlane> = 0.571 ± 0.004 c <bOutOfPlane> = 0.540 ± 0.004 c RInPlane = 11.1 ± 0.2 fm ROutOfPlane = 12.1 ± 0.2 fm Life time (t) = 8.4 ± 0.2 fm/c Emission duration = 1.9 ± 0.2 fm/c c2/dof = 120 / 86 v2 HBT Latest paper (long legacy), F.R and M.Lisa nucl-th/0312024

  14. Parameterization  parametersSystem deformation in the Blast Wave Y Time X • Final state eccentricity from • v2 • HBT with respect to reaction plane Time

  15. Is flow partonic, hadronic or both? Now, that we can characterize flow, let’s ask the most important question:

  16. Is flow partonic, hadronic or both? • Only the models with a partonic stage reproduce flow data • Hadronisation by quark coalescence. Wait for R. Fries’ talk. • Are resonance yields affected by a hadronic rescattering stage? • Do f, X and W flow? Do they flow as p, K, p? • What is the flow of photons not coming from hadron decay? • Do charm hadrons flow? f, X, W p, K, p Hadronic Partonic Hadronisation Resonances Sketch by S. Bass Photons (from hadrons) Photons (prompt) Photons (thermal) Charm Charm

  17. Resonance yields consistent with a hadronic re-scattering stage • Generation/suppression according to x-sections p p D p Preliminary r/p p p D L* D/p More D K Chemical freeze-out f/K f Ok p p r p p Less K* K*/K p r K* Less L* L*/L K K f 0.1 0.2 0.3 K

  18. Significant X and W v2Multi-Strange Baryon flow STAR preliminary AuAu √s = 200 GeV This afternoon’s talk by J. Castillo

  19. Do X and W flow as p, K, p?Blast Wave  no (RHIC), hydro  ? Hydro (P. Kolb & U. Heinz) nucl-th/0305084 Blast wave fits Central AuAu √s = 200 GeV X and W, STAR preliminary Preliminary NA57 and NA49 data Different flow profile for NA57

  20. The Blast Wave side of the story Early freeze-out of X and W p,K,p spectra PHENIX (box) & STAR (circle) __ 1 s contour 0.6 WandX spectra STAR preliminary 0.4 <bT> and eccentricity Glauber ~ 0.3 • v2 (STAR preliminary) 0.2 p asHBT (STAR) p,K,p v2 (PHENIX) Initial flow ~0 300 200 100 Temperature (MeV) Initial state Time

  21. Photon flow fully driven by p0 flow? This afternoon’s talk by M. Kaneta vertical bar : stat. error curves, gray box : sys. error Note : Inclusive photon = including all of the decay effect from hadrons , 200 GeV Au+Au , 200 GeV Au+Au , 200 GeV Au+Au phenix preliminary phenix preliminary phenix preliminary pT [GeV/c]

  22. Electron v2 and Charm flow Talk by M. Kaneta, posters by S. Sakai, T. Hashiya 0.3 0.25 0.2 0.15 0.1 0.05 0 -0.05 -0.1 The data point : on <pT> in the bin horizontal bar : RMS of dN/dpT non-photonic electron v2 J. Nagle, S. Kelly, M. Gyulassy, S.B. JN, Phys. Lett. B 557, pp 26-32 And talk by S.Kelly 0 12 3 pT [GeV/c]

  23. Summary • A wealth of data probing flow becoming available • v1, v2, v4, v6, spectra, and two-particle correlations • Data described quantitatively and self-consistently by parameterizations • What about models? (please release your code) • Data pointing to flow being a combination of partonic and hadronic flow at RHIC • Final conclusion pending … • Outlook: • More f, X, W, charm, photons, non-id correlations • My wish: so much data will make the models converge

  24. BudaLund M. Csanád, T. Csörgő, B. Lörstad and A. Ster (Tuesday’s talk and poster) Spectra Source size (HBT) nucl-th/0311102 and nucl-th/0310040

  25. Hadronization by quark coalescence: v2 scaling by quarks Approximate validity range Wait for R.Fries’s talk for full glory details

  26. Simultaneous fit to Spectra v2 HBT radii Example of self-consistencyThe Blast Wave parameterization

  27. Mean flow velocity higher than 0.5 c Flow increases with energy density as quantified by dN/dY/Area No scaling with s No scaling rapidity But different flow profile used by BRAHMS Quantifying the flow strength Y=0 and 1 Y=3 Y=2

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