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Some aspects of

Some aspects of. The BlastWave parameterization of the Freeze-out configuration at RHIC. Particle Correlations and Collective Effects. at RHIC in the soft sector. from some of the data. NOT an overview talk by. Mike Lisa Ohio State University.

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Some aspects of

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  1. Some aspects of The BlastWave parameterization of the Freeze-out configuration at RHIC Particle Correlations and Collective Effects at RHIC in the soft sector from some of the data NOT an overview talk by Mike Lisa Ohio State University malisa - CIPANP2003 - NYC

  2. The BlastWave parameterization of the Freeze-out configuration at RHIC • First motivation – pT spectra • Application to HBT radii • Out-of-the-box application to correlations of non-identical particles • Generalization to non-central collisions • v2(pT,m) • Azimuthally-sensitive HBT • Conclusions malisa - CIPANP2003 - NYC

  3. Heinz & Kolb, hep-ph/0204061 Hydro @ RHIC: trouble in x-space, good in p-space malisa - CIPANP2003 - NYC

  4. Teaney, Lauret & Shuryak, nucl-th/0110037 “Box” unrealistic? Reasonable to consider third parameter: “skin thickness” (more later) Heinz & Kolb, hep-ph/0204061 Hydrodynamics & (soft sector) pT spectra at RHIC • (Boost-invariant) hydro: good reproduction of (,K,p) pT spectra near midrapidity • Spectra do not scale with pT (or mT) • shape depends on mass: superposition of thermal motion on collective flow velocity field • Transverse fluid rapidity yT (aka ) ~ linear in r • Schnedermann et al (’93): 2-parameter (T, max) “hydro-inspired” functional form to fit spectra. • Useful to extract thermal, collective energy Note hard-edge (“box profile”) approximation malisa - CIPANP2003 - NYC

  5. Tth = 107 MeV b = 0.55 T, 0 from published (130 GeV) pT spectra • reasonable dependence on centrality • ~consistent with other BlastWaves M. Kaneta malisa - CIPANP2003 - NYC

  6. 10 y (fm) 0 -10 -10 0 10 x (fm) 10 y (fm) pions kaons 0 protons -10 -10 0 10 x (fm) Spatial implications – central collisions • pT spectra are insensitive to spatial scale R • However, two-particle correlations probe R → “new” parameter (not really) • Also: gradients in collective velocity + finite geometric scale →space-momentum correlations • Homogeneity scale decreases with pT • Spatial separation between different-mass particles =0.4 =0.8 R=10 fm, T=0.1 GeV, 0=0.9 malisa - CIPANP2003 - NYC

  7. 0 Timescale considerations • SSH: Freeze-out at constant proper time 0 • pT spectra insensitive to 0→ another “hidden” parameter to explore with 2-particle correlations (e.g. RL)  0 • Finally, 2-particle correlations sensitive to emissionduration, as well as evolution duration 0→ generalize SSH model • pT spectra insensitive to  malisa - CIPANP2003 - NYC

  8. central midcentral peripheral Fits to published (130 GeV) pion HBT • ~consistent with STAR • PHENIX transverse fall faster than BW • Imperfect fit suggests short evolution and (especially) emission timescales • Evolution of source size, evolution time with centrality reasonable malisa - CIPANP2003 - NYC

  9. STAR, QM01; NPA698, 177c (2002) f “Standard” Coulomb CC No Coulomb CC Detour: Recent analysis developments • RHIC analyses used “standard” Coulomb correction, used by previous experiments • “apples-to-apples” extension of systematics • Effects of “diluting” CC (resonances, etc) explored & reported @ QM01 • Ro affected most • Y2 data: dilution effect vs pT, centrality • RO/RS ~ 10-15% increase when f =  ≈ 0.5 • More correct CC method of Bowler (’91) & Sinyukov (’98), used by CERES (’02) • Similar effect on radii as dilution with f =  • In “right” direction, but does not solve • RO/RS problem • RL problem • BW: ~2 fm/c / finite aS or… broken! malisa - CIPANP2003 - NYC

  10. BlastWave A check from another angle:Kaon-pion correlations: dominated by Coulomb STAR preliminary; F. Retiere, QM02; central Au130Au Smaller source  stronger (anti)correlation K- correlation ~well-described by BW with same parameters as spectra, HBT But with non-identical particles, we can access more information… malisa - CIPANP2003 - NYC

  11. Catching up: cosY  0 • long interaction time • strong correlation • Moving away: cosY  0 • short interaction time • weak correlation • Ratio of both scenarios allow quantitative study of the emission asymmetry Initial idea: probing emission-time ordering purple K emitted first green p is faster purple K emitted first green p is slower Crucial point: kaon begins farther in “out” direction (in this case due to time-ordering) malisa - CIPANP2003 - NYC

  12. 10 y (fm) 0 -10 -10 0 10 x (fm) 10 y (fm) pions kaons 0 protons -10 -10 0 10 x (fm) Spatial implications – central collisions • pT spectra are insensitive to spatial scale R • However, two-particle correlations probe R → “new” parameter (not really) • Also: gradients in collective velocity + finite geometric scale →space-momentum correlations • Homogeneity scale decreases with pT • Spatial separation between different-mass particles =0.4 =0.8 Unavoidable hierarchy of emission zones R=10 fm, T=0.1 GeV, 0=0.9 malisa - CIPANP2003 - NYC

  13. Comparison (no fit) to preliminary K- STAR preliminary; F. Retiere, QM02; central Au130Au • overall scale reproduced (CF) • direction of shift reproduced(kaons emitted further out) • magnitude of effect overpredicted • data: r* = 5.6 fm • BW: r* = 6.9 fm malisa - CIPANP2003 - NYC

  14. Summary for soft central data • Hydro-inspired functional form “designed” for spectra fits: T, 0 • Application to x-space probes ( HBT, K- correlations) • scales of “non-parameters” R, 0 become meaningful/measurable • “addition” (generalization) of emission timescale  • Direct implications for x-space probes: • shrinking emission region with increasing pT • shifted emission regions for non-identical particles confirmed semi-quantitatively On to non-central collisions… malisa - CIPANP2003 - NYC

  15. Heinz & Kolb hep-ph/0111075 Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c malisa - CIPANP2003 - NYC

  16. Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c in-plane geometry in-plane flow • elliptic flow quickly “self-quenches” as geometry  in-plane-extended Heinz & Kolb, hep-th/0204061 malisa - CIPANP2003 - NYC

  17. later hadronic stage? Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • elliptic flow quickly “self-quenches” as geometry  in-plane-extended • Effect of (presumed) hadronic stage? • little effect on v2 (@ RHIC) Teaney, Lauret, & Shuryak, nucl-th/0110037 malisa - CIPANP2003 - NYC

  18. later hadronic stage? hydro only hydro+hadronic rescatt STAR PHENIX Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • elliptic flow quickly “self-quenches” as geometry  in-plane-extended • Effect of (presumed) hadronic stage? • little effect on v2 (@ RHIC) • RO/RS, RL increase calculation: Soff, Bass, Dumitru, PRL 2001 malisa - CIPANP2003 - NYC

  19. later hadronic stage? in-plane-extended out-of-plane-extended Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • elliptic flow quickly “self-quenches” as geometry  in-plane-extended • Effect of (presumed) hadronic stage? • little effect on v2 (@ RHIC) • RO/RS, RL increase • freezeout geometry becomesin-plane-extended Teaney, Lauret, & Shuryak, nucl-th/0110037 malisa - CIPANP2003 - NYC

  20. later hadronic stage? Noncentral collisions • intrinsic anisotropy in entrance channel  preferential in-plane expansion (elliptic flow) • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • elliptic flow quickly “self-quenches” as geometry  in-plane-extended • Effect of (presumed) hadronic stage? • little effect on v2 (@ RHIC) • RO/RS,RLincrease • freezeout geometry becomesin-plane-extended timescale effects (indep in BW) Teaney, Lauret, & Shuryak, nucl-th/0110037 malisa - CIPANP2003 - NYC

  21. p central midcentral peripheral Anisotropy in BW Ry RX • 0 → 0 + a·cos(2S) • in-plane cells boost more • R→ RX, RY • more cells boosting in-plane • Global fit to published Y1 • pT spectra •  HBT radii • v2(pT,m) • Main “surprise”: short timescales • supported by out-of-plane freezeout geometry malisa - CIPANP2003 - NYC

  22. v2 pT (GeV/c) v2 nch / nmax An alternative scenario – who needs flow? • saturation model • v2 : correlation b/t minijet products • no relationship to (true) reaction plane! • Can this be checked? Y. Kotchegov, K. Tuchin hep-ph0203213, nucl-th0207037 malisa - CIPANP2003 - NYC

  23. First indirect indications of x-space anisotropy @ RHIC STAR, PRL 87 182301 (2001) Rside small Rside large check directly with azimuthally-sensitive HBT Rs2 [no-flow expectation] fp malisa - CIPANP2003 - NYC

  24. Au+Au 130 GeV minbias • Minbias asHBT well-reproduced with same BlastWave from minbias v2(pT,m) • Ry = 11.4 fm • Rx = 10.8 fm • 0 = 8.3 fm/c •  = 0 ( → ~1.5 fm/c w/ Bowler CC)) • Consistent picture – convincing argument for bulk flow scenario • Saturation ???? s2 = 0.045 asHBT versus BlastWave • asHBT: geometry dominates dynamics • Source out-of-plane extended BAIL malisa - CIPANP2003 - NYC

  25. Further systematics in Au+Au 200 GeV Centrality cuts kT-integrated 12  bins Centrality cuts kT-integrated 12  bins kT cuts Mid-central 4  bins • Oscillation phases: out-of-plane extended source • Source size increases, oscillations decrease with increasing centrality • 0th and 2nd harmonics only • Average size (0th harmonic) falls with kT • Mild evolution of 2nd harmonic with kT malisa - CIPANP2003 - NYC

  26. central midcentral peripheral “Grand summary” of asHBTFourier Coefficients n = 0 n = 2 • Centrality- and kT- dependence of the -dependence summarized concisely by Fourier coefficients malisa - CIPANP2003 - NYC

  27. central midcentral peripheral “Grand summary”Fourier Coefficients n = 0 n = 2 • Centrality- and kT- dependence of the -dependence summarized concisely by Fourier coefficients • Hydro predictions (*): b = 6 fm “RHIC” source “LHC” (IPES) source • Scale of homogeneity lengths off • Phase/magnitude of oscillations from “RHIC” source in the ballpark • significance ? (*) Heinz & Kolb, hep-ph/0204061 malisa - CIPANP2003 - NYC

  28. Evolution of spatial anisotropy • BW fit to preliminary STAR asHBT@ 200 Gev • Out-of-plane-extended freezeout geometry for all centralities • init from Glauber • final from asHBT • further constraint on evolution timescale (and dynamic models!!) malisa - CIPANP2003 - NYC

  29. Summary • Flow scenario gives a consistent picture of low-pT dynamics at RHIC • BlastWave – • toy “model” designed to capture essential elements of scenario • parameters ~constrained by global fit to • spectra • HBT • v2(pT,m) • checks: • asHBT – “proof” that v2 is geometrically driven • K-pi – “proof” of x-p correlations from radial flow malisa - CIPANP2003 - NYC

  30. BW - A rough picture “Reality” BlastWave version • With some assumptions/prior knowledge, can identify gross properties • relative scale of child/animal • orientation/posture of child • etc. • But NOT details: e.g. child’s expression, texture on pajamas More importantly: cannot tell how/why the child got there – picture can only provide feedback to true explanation (model) malisa - CIPANP2003 - NYC

  31. Is BW “the” answer • I’m convinced that it contains the major driving elements of the truth– i.e. it is approximately right • Hydro gives similar functional form • It gets trends in data qualitatively and approximately quantitatively, even for new observables for which it was not “designed” • But I’m not yet totally decided how much of a “precision tool” it is. • Can we learn something physical from small discrepancies from BW? (e.g. different flow, temp for strange particles) or is that just a matter of tuning (e.g. as) and a limitation, period. • Get a picture of me, and show it also in low resolution, and also distorted. That’s how I think of the BW representation of reality. Good only for broad strokes. • Also: BW only describes the freezeout configuration (how big, how hot, how much flow, how long it took to get there, how long freezeout lasted) – it does NOT describe the evolution, so is not really a physical “model” malisa - CIPANP2003 - NYC

  32. Discrepancies w/ BW Show Zhangbu/Nu’s plot of slope versus mass – strange particles different But then show effect of as on spectra – could “explain” it (needs to be investigated) Conclusion: who knows? Maybe strange particles ARE different. Still not sure if BW Is really such a “precision tool” to say something like that malisa - CIPANP2003 - NYC

  33. Linked-to slides follow malisa - CIPANP2003 - NYC

  34. 10 y (fm) pions kaons 0 protons -10 -10 0 10 x (fm) Spatial implications – central collisions as=0.3 • pT spectra are insensitive to spatial scale R • However, two-particle correlations probe R → “new” parameter (not really) • Also: gradients in collective velocity + finite geometric scale →space-momentum correlations • Homogeneity scale decreases with pT • Spatial separation between different-mass particles 10 y (fm) =0.4 0 -10 -10 0 10 x (fm) =0.8 Unavoidable hierarchy of emission zones R=10 fm, T=0.1 GeV, 0=0.9 malisa - CIPANP2003 - NYC

  35. malisa - CIPANP2003 - NYC

  36. Possible to “see” via HBT relative to reaction plane? fp=90° • for out-of-plane-extended source, expect • large Rside at 0 • small Rside at 90 Rside (small) 2nd-order oscillation Rside (large) fp=0° Rs2 [no flow expectation] fp malisa - CIPANP2003 - NYC

  37. dashed solid T (MeV) 135  20 100  24 0(c) 0.52  0.02 0.54  0.03 a (c) 0.09  0.02 0.04  0.01 S2 0.0 0.04  0.01 Indirect indications of x-space anisotropy @ RHIC STAR, PRL 87 182301 (2001) • v2(pT,m) globally well-fit by hydro-inspired “blast-wave” temperature, radial flow consistent with fits to spectra  anisotropy of flow boost spatial anisotropy (out-of-plane extended) malisa - CIPANP2003 - NYC

  38. A shot at 200 GeV data malisa - CIPANP2003 - NYC

  39. Blast wave in the right ballpark Need to decrease the uncertainties In progress Need to increase the acceptance Need new detector in STAR Points: preliminary STAR data Plain line: Blast wave calculation Dash line: BW without time Shifts and BW p-K p-p K-p malisa - CIPANP2003 - NYC

  40. Star preliminary CENTRAL DATA Star preliminary Star preliminary malisa - CIPANP2003 - NYC

  41. Star preliminary PERIPHERAL DATA Star preliminary Star preliminary malisa - CIPANP2003 - NYC

  42. malisa - CIPANP2003 - NYC

  43. here’s what’s next: • for non-central collisions, we already know (hydro – show kolb density contours) that there is anisotropy in flow field, and in geometric shape • one drives the other– entrance-channel anisotropy leads to flow gradient anisotropies, which means more flow in-plane (elliptic flow) • hydro does good job also on THIS p-space observable (v2) [kolb vs STAR v2] • hydro is not full story– what about later hadronic stage? • little effect on v2 [Teaney plot] • but (reminder) significant effect on HBT radii [bass plot] (*and it’s even worse for Rlong) • probably due to timescale [Teaney plot] • to get a handle on that, look at (final) geometric anisotropy – it doesn’t saturate as quickly as does momentumspace anisotropy, so can play the role of a “clock” [kolb plot] • both kolb and teaney hydro say out-of-plane at RHIC, but if hadronic stage included, then should be in-plane. [teaney plot] • let’s see – use blastwave to probe flow and shape anisotropy!!! • This will mean that blastWave gets generalized – 2 more parameters • show PID v2 fit of me/Fabrice (centrality cut) – good • variation with centrality makes sense etc. • show STAR minbias PID fit published (don’t go into details of parameters) • check with asHBT! Randy • same parameters– good reproduction of data malisa - CIPANP2003 - NYC

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