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Femtoscopy in heavy ion collisions - Part 2

!. !. “School” lecture. Femtoscopy in heavy ion collisions - Part 2. Mike Lisa The Ohio State University. Lecture I - basics and sanity check Motivation (brief) Formalism (brief reminder) accessible geometric substructure Some experimental details 2 decades * of data systematics

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Femtoscopy in heavy ion collisions - Part 2

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  1. ! ! “School” lecture Femtoscopy in heavy ion collisions - Part 2 Mike Lisa The Ohio State University The Berkeley School - Femtoscopy - malisa

  2. Lecture I - basics and sanity check Motivation (brief) Formalism (brief reminder) accessible geometric substructure Some experimental details 2 decades* of data systematics system size: AB, |b|, Npart... system shape: (P,b) Lecture II - dynamics (insanity check?) data systematics [cnt’d] boost-invariance?: Y transverse dynamics: kT, mT new substructure: m1≠m2 Interpretations (& puzzles) Messages from data itself Model comparisons Prelim. comparison: pp, dA Summary Outline * in time and in sNN The Berkeley School - Femtoscopy - malisa

  3. ? in-plane-extended Motivation Formalism Experiment Trends Models out-of-plane-extended Strongly-interacting 6Li released from an asymmetric trap O’Hara, et al, Science 298 2179 (2002) What can we learn? transverse FO shape + collective velocity  evolution time estimate check independent of RL(pT) Teaney, Lauret, & Shuryak nucl-th/0110037 The Berkeley School - Femtoscopy - malisa

  4. RY Spectra RX Motivation Formalism Experiment Trends Models v2 HBT Blast wave : the truth, or something like it F. Retière , QM04 F. Retière & MAL PRC70 044907 (2004) • generalized anisotropic BW in ubiquitous use • consistent picture capturing essence of data • homo. region  “whole source” with realistic flow gradients The Berkeley School - Femtoscopy - malisa

  5. out side Motivation Formalism Experiment Trends Models long out-side in no-flow scenario... U. Wiedemann PR C57 266 (1998) MAL, U. Heinz, U. Wiedemann PL B489 287 (2000) Extracting FO shape/size • 2nd - order oscillations in radii (n>2 negligible) • characterize each kT bin with 7 numbers: R2os,0 = 0 by symmetry [Heinz, Hummel, MAL, Wiedemann PRC66, 044903] F. Retière & MAL PRC70 044907 (2004) The Berkeley School - Femtoscopy - malisa

  6. Motivation Formalism Experiment Trends Models in no-flow scenario... U. Wiedemann PR C57 266 (1998) MAL, U. Heinz, U. Wiedemann PL B489 287 (2000) Extracting FO shape/size • 2nd - order oscillations in radii (n>2 negligible) • characterize each kT bin with 7 numbers: R2os,0 = 0 by symmetry [Heinz, Hummel, MAL, Wiedemann PRC66, 044903] /2 continues to be good approximation even with flow! (~30%) F. Retière & MAL PRC70 044907 (2004) The Berkeley School - Femtoscopy - malisa

  7. Motivation Formalism Experiment Trends Models in no-flow scenario... U. Wiedemann PR C57 266 (1998) MAL, U. Heinz, U. Wiedemann PL B489 287 (2000) Extracting FO shape/size • 2nd - order oscillations in radii (n>2 negligible) • characterize each kT bin with 7 numbers: R2os,0 = 0 by symmetry [Heinz, Hummel, MAL, Wiedemann PRC66, 044903] continues to be good approximation even with flow! (~30%) F. Retière & MAL PRC70 044907 (2004) The Berkeley School - Femtoscopy - malisa

  8. central collisions mid-central collisions Motivation Formalism Experiment Trends Models peripheral collisions Measured final source shape STAR, PRL93 012301 (2004) Expected evolution: ? The Berkeley School - Femtoscopy - malisa

  9. 2.5 Rfinal/Rinitial initial= final 2 Motivation Formalism Experiment Trends Models 1.5 1 0 100 200 300 400 Npart Evolution of size and shape @RHIC STAR PRC71 044906 (2005) STAR PRL93 012301 (2004) ~ x2 size increase ~ 1/2 shape reduction Initial size/shape estimated by Glauber calculation The Berkeley School - Femtoscopy - malisa

  10. Evolution ahead Detour The Berkeley School - Femtoscopy - malisa

  11. Motivation Formalism Experiment Trends Models asHBT systematics (1/100 * sNN) •  = 0-2 (not 0-)first-order plane used • similar oscillations in purely transverse radii • out-long & side-long? • new symmetry! Au+Au sNN = 2.3 GeV; b5 fm E895, PLB496 1 (2000) The Berkeley School - Femtoscopy - malisa

  12. Motivation Formalism Experiment Trends Models out-side-long versus x-y-z side y K • Source in b-fixed system: (x,y,z) • Space/time entangled in pair system (xO,xS,xL) out f x b (several terms vanish @ pT = y = 0) U. Wiedemann, PRC 57, 266 (1998) MAL, U. Heinz, U. Wiedemann PLB 489, 287 (2000) The Berkeley School - Femtoscopy - malisa

  13. y 2nd-harmonic oscillations from elliptical transverse shape x b 1st-harmonic oscillations: spatial tilt angle qS y x qs z (Beam) Coordinate space! First-order information in HBT(f) The Berkeley School - Femtoscopy - malisa

  14. f () Data: p- correlation functionsAu(4 AGeV)Au, b4-8 fm 2D projections 1D projections, f=45° C(q) out side long lines: projections of 3D Gaussian fit • 6 components to radius tensor: i, j = o,s,l E895, PLB 496 1 (2000) The Berkeley School - Femtoscopy - malisa

  15. f () Cross-term radii Rol, Ros, Rslquantify “tilts” in correlation functions fit results to correlation functions Mike Lisa: thicker lines!!! bigger symbols!! have 2 GeV handy Lines: Simultaneous fit to HBT radii to extract underlying geometry The Berkeley School - Femtoscopy - malisa

  16. qS=47° qS=33° qS=37° y z y y z z x x ’ x ’ x x ’ x similar to naïve overlap: b~5 fm 3 fm Images of p--emitting sources (scaled ~ x1014) Mike Lisa: 1 fm = 1/4” 2 AGeV 4 AGeV 6 AGeV Large, positive tilt angles The Berkeley School - Femtoscopy - malisa

  17. p+ 6 AGeV z (fm) x (fm) RQMD Au(2GeV)Au Opposing average tilts in p, x & the physics of p flow • p “antiflow” (negative tilt in p-space) • x-space tilt in positive direction •  non-hydro nature of p flow (@ AGS) B. Caskey, E895 The Berkeley School - Femtoscopy - malisa

  18. AGS: FO  init RHIC: FO < init (approximately same centrality) sNN (GeV) • transverse shape: • non-trivial excitation function • increased flow*time  rounder FO geometry @ RHIC • insufficient [flow]x[time] to become in-plane The Berkeley School - Femtoscopy - malisa

  19.  (o) y x qs sNN (GeV) z (Beam) AGS • transverse shape: • non-trivial excitation function • increased flow*time  rounder FO geometry @ RHIC • insufficient [flow]x[time] to become in-plane • Spatial orientation: • another handle on flow & time • HUGE tilts @ AGS!! • RHIC? • QGP-induced orientation? STAR: soon ? ? The Berkeley School - Femtoscopy - malisa

  20. v1 predictions (QGP invoked) x-p transverse-longitudinal coupling may be affected in early (v1) stage L.P. Csernai, D. Rohrich: Phys. Lett. B 458 (1999) 454 J. Brachmann et al., Phys. Rev. C. 61 024909 (2000) The Berkeley School - Femtoscopy - malisa

  21.  (o) y x qs sNN (GeV) z (Beam) AGS • transverse shape: • non-trivial excitation function • increased flow*time  rounder FO geometry @ RHIC • insufficient [flow]x[time] to become in-plane • Spatial orientation: • another handle on flow & time • HUGE tilts @ AGS!! • RHIC? • QGP-induced orientation? • requires true 3D dynamical model (explicitly non-B.I.) STAR: soon ? ? ? The Berkeley School - Femtoscopy - malisa

  22. Spectra Evolution ahead v2 Resume legal speed HBT x2 size increase & decreasing deformation -- ?collective expansion? -- The Berkeley School - Femtoscopy - malisa

  23. Decreasing R(pT) • usually attributed to collective flow • flow integral to our understanding of R.H.I.C.; taken for granted • femtoscopy the only way to confirm x-p correlations – impt check Kolb & Heinz, QGP3 nucl-th/0305084 The Berkeley School - Femtoscopy - malisa

  24. Decreasing R(pT) • usually attributed to collective flow • flow integral to our understanding of R.H.I.C.; taken for granted • femtoscopy the only way to confirm x-p correlations – impt check • Non-flow possibilities • cooling, thermally (not collectively) expanding source • combo of x-t and t-p correlations early times: small, hot source late times: large, cool source The Berkeley School - Femtoscopy - malisa

  25. Decreasing R(pT) • usually attributed to collective flow • flow integral to our understanding of R.H.I.C.; taken for granted • femtoscopy the only way to confirm x-p correlations – impt check • Non-flow possibilities • cooling, thermally (not collectively) expanding source • combo of x-t and t-p correlations MAL et al, PRC49 2788 (1994) The Berkeley School - Femtoscopy - malisa

  26. Decreasing R(pT) • usually attributed to collective flow • flow integral to our understanding of R.H.I.C.; taken for granted • femtoscopy the only way to confirm x-p correlations – impt check • Non-flow possibilities • cooling, thermally (not collectively) expanding source • combo of x-t and t-p correlations • hot core surrounded by cool shell • important ingredient of Buda-Lund hydro picturee.g. Csörgő & LörstadPRC54 1390 (1996) The Berkeley School - Femtoscopy - malisa

  27. Each scenario generates x-p correlations • Decreasing R(pT) • usually attributed to collective flow • flow integral to our understanding of R.H.I.C.; taken for granted • femtoscopy the only way to confirm x-p correlations – impt check but… x2-p correlation: yes x-p correlation: yes • Non-flow possibilities • cooling, thermally (not collectively) expanding source • combo of x-t and t-p correlations • hot core surrounded by cool shell • important ingredient of Buda-Lund hydro picturee.g. Csörgő & LörstadPRC54 1390 (1996) x2-p correlation: yes x-p correlation: no t x2-p correlation: yes x-p correlation: no The Berkeley School - Femtoscopy - malisa

  28. pT T • flow-dominated “models” can reproduce soft-sector x-space observables • imply short timescales • however, are we on the right track? [flow] • puzzles?  check your assumptions! • look for flow’s “special signature”x-p correlation • In flow pictures, low-pT particles emitted closer to source’s center (along “out”) • non-identical particle correlations(FSI at low v) probe: • (x1-x2)2 (as does HBT) • x1-x2  K p [click for more details on non-id correlations] F. Retiere & MAL, nucl-th/0312024 Csanád, Csörgő, Lörstad nucl-th/0311102 and nucl-th/0310040 The Berkeley School - Femtoscopy - malisa

  29. T T x (fm) QM02 x (fm) A. Kisiel (STAR) QM04 • extracted shift in emission point x1-x2 consistent w/ flow-dominated blastwave • In flow pictures, low-pT particles emitted closer to source’s center (along “out”) • non-identical particle correlations(FSI at low v) probe: • (x1-x2)2 (as does HBT) • x1-x2 The Berkeley School - Femtoscopy - malisa

  30. LPSW(05) - DATA in color-- experimentalist’s plot Motivation Formalism Experiment Trends Models what agreement!! (what agreement?) Strong flow confirmed by all expts... The Berkeley School - Femtoscopy - malisa

  31. Motivation Formalism Experiment Trends Models Strong flow confirmed by all expts... Central (~10%) AuAu (PbPb) collisions at y~0 The Berkeley School - Femtoscopy - malisa

  32. Motivation Formalism Experiment Trends Models Another implication of strong flow: ~mT scaling The Berkeley School - Femtoscopy - malisa

  33. inconsistent with boost-invariance Motivation Formalism Experiment Trends Models PHOBOS nucl-ex/0410022 Some longitudinal systematics consistent with boost-invariance The Berkeley School - Femtoscopy - malisa

  34. beam “Dynamic” BI without “Chemical” BI ? Only femtoscopy can tell! The Berkeley School - Femtoscopy - malisa

  35. beam “Dynamic” BI without “Chemical” BI ? Only femtoscopy can tell! The Berkeley School - Femtoscopy - malisa

  36. sizes and offsets in impact parameter and longitudinal directions C E877, Miskowiec CRIS’98 nucl-ex/9808003 p-- Motivation Formalism Experiment Trends Models 10 fm qX (GeV/c) b qY (GeV/c) qZ (GeV/c) z Greater detail - -p correlations @ AGS The Berkeley School - Femtoscopy - malisa

  37. Summary - very brief.More in Friday’s discussion The Berkeley School - Femtoscopy - malisa

  38. R = 1.2 (fm)•A1/3 Summary - very brief.More in Friday’s discussion • Part I • space-time THE special aspect of our field • systematics pass sanity check • Data show remarkable consistency • HUGE range of systematics, b (mag and direction), pT, m1m2, y, AB • size • shape • orientation in 3D space • detailed dynamic substructure in all directions including shifts • At a given s, flow-dominated scenario strongly indicated. Can work (Blast Wave) • (Unfortunately?) 2 decades of experimental effort over 2 decades of s • very little changes • scaling with final multiplicity, not A... progress? The Berkeley School - Femtoscopy - malisa

  39. final words (for today) • We are measuring system geometry • Space and time geometry (in detail) hardly changesAGS RHIC • This astounding fact is the 0th HBT Puzzle, and much more important/troubling than the 1st Puzzle (model failures) • generic expectation: entropy & latent heat / “softest point” • Given the importance of spacetime to RHI and QGP, this deserves our attention, despite its being a wart on otherwise “perfect” story The Berkeley School - Femtoscopy - malisa

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