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Azimuthally-sensitive HBT in STAR

Azimuthally-sensitive HBT in STAR. Mike Lisa Ohio State University. Motivation Noncentral collision dynamics Azimuthally-sensitive interferometry & previous results STAR results Hydrodynamic predictions for RHIC and “LHC” Summary. Central collision dynamics @ RHIC.

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Azimuthally-sensitive HBT in STAR

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  1. Azimuthally-sensitive HBT in STAR Mike Lisa Ohio State University • Motivation • Noncentral collision dynamics • Azimuthally-sensitive interferometry & previous results • STAR results • Hydrodynamic predictions for RHIC and “LHC” • Summary Mike Lisa - XXXII ISMD - Alushta, Ukraine

  2. Central collision dynamics @ RHIC • Hydrodynamics reproduces p-space aspects of particle emission up to pT~2GeV/c (99% of particles) hopes of exploring the early, dense stage Mike Lisa - XXXII ISMD - Alushta, Ukraine Heinz & Kolb, hep-th/0204061

  3. Central collision dynamics @ RHIC • Hydrodynamics reproduces p-space aspects of particle emission up to pT~2GeV/c (99% of particles) hopes of exploring the early, dense stage • x-space is poorly reproduced • model source lives too long and disintegrates too slowly? • Correct dynamics signatures with wrong space-time dynamics? • Turn to richer dynamics of non-central collisions for more detailed information Mike Lisa - XXXII ISMD - Alushta, Ukraine Heinz & Kolb, hep-th/0204061

  4. Noncentral collision dynamics • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • system response  EoS • early thermalization indicated Heinz & Kolb, hep-ph/0111075 hydro evolution • Dynamical models: • x-anisotropy in entrance channel  p-space anisotropy at freezeout • magnitude depends on system response to pressure Mike Lisa - XXXII ISMD - Alushta, Ukraine

  5. Effect of dilute stage later hadronic stage? hydro evolution • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.0 GeV/c • system response  EoS • early thermalization indicated • dilute hadronic stage (RQMD): • little effect on v2 @ RHIC Mike Lisa - XXXII ISMD - Alushta, Ukraine Teaney, Lauret, & Shuryak, nucl-th/0110037

  6. Effect of dilute stage later hadronic stage? hydro only hydro+hadronic rescatt STAR PHENIX hydro evolution • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • system response  EoS • early thermalization indicated • dilute hadronic stage (RQMD): • little effect on v2 @ RHIC • significant (bad) effect on HBT radii calculation: Soff, Bass, Dumitru, PRL 2001 Mike Lisa - XXXII ISMD - Alushta, Ukraine

  7. Effect of dilute stage later hadronic stage? hydro evolution • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • system response  EoS • early thermalization indicated • dilute hadronic stage (RQMD): • little effect on v2 @ RHIC • significant (bad) effect on HBT radii • related to timescale? - need more info Mike Lisa - XXXII ISMD - Alushta, Ukraine Teaney, Lauret, & Shuryak, nucl-th/0110037

  8. Effect of dilute stage later hadronic stage? in-plane-extended out-of-plane-extended hydro evolution • hydro reproduces v2(pT,m) (details!) @ RHIC for pT < ~1.5 GeV/c • system response  EoS • early thermalization indicated • dilute hadronic stage (RQMD): • little effect on v2 @ RHIC • significant (bad) effect on HBT radii • related to timescale? - need more info • qualitative change of freezeout shape!! • important piece of the puzzle! Mike Lisa - XXXII ISMD - Alushta, Ukraine Teaney, Lauret, & Shuryak, nucl-th/0110037

  9. Possible to “see” via HBT relative to reaction plane? fp=90° Rside (small) Rside (large) fp=0° • for out-of-plane-extended source, expect • large Rside at 0 • small Rside at 90 2nd-order oscillation Rs2 [no flow expectation] fp Mike Lisa - XXXII ISMD - Alushta, Ukraine

  10. “Traditional HBT” - cylindrical sources K Rout Rside Decompose q into components: qLong: in beam direction qOut : in direction of transverse momentum qSide:  qLong & qOut (beam is into board) Mike Lisa - XXXII ISMD - Alushta, Ukraine

  11. Anisotropic sources Six HBT radii vs f side y K out • Source in b-fixed system: (x,y,z) • Space/time entangled in pair system (xO,xS,xL) fp x b ! • explicit and implicit (xmxn(f)) dependence on f Mike Lisa - XXXII ISMD - Alushta, Ukraine Wiedemann, PRC57 266 (1998).

  12. Symmetries of the emission function I. Mirror reflection symmetry w.r.t. reactionplane (for spherical nuclei):  with II. Point reflection symmetry w.r.t. collision center (equal nuclei):  with Heinz, Hummel, MAL, Wiedemann, nucl-th/0207003 Mike Lisa - XXXII ISMD - Alushta, Ukraine

  13. Fourier expansion of HBT radii @ Y=0 Insert symmetry constraints of spatial correlation tensor into Wiedemann relations and combine with explicit F-dependence: Note: These most general forms of the Fourier expansions for the HBT radii are preserved when averaging the correlation function over a finite, symmetric window around Y=0. Relations between the Fourier coefficients reveal interplay between flow and geometry, and can help disentangle space and time Mike Lisa - XXXII ISMD - Alushta, Ukraine Heinz, Hummel, MAL, Wiedemann, nucl-th/0207003

  14. Anisotropic HBT results @ AGS (s~2 AGeV) out side long 40 R2 (fm2) 20 os ol sl 10 0 -10 0 0 0 180 180 180 fp (°) Au+Au 2 AGeV; E895, PLB 496 1 (2000) xside xout K fp = 0° • strong oscillations observed • lines: predictions for static (tilted) out-of-plane extended source  consistent with initial overlap geometry Mike Lisa - XXXII ISMD - Alushta, Ukraine

  15. Meaning of Ro2(f) and Rs2(f) are clearWhat about Ros2(f) ? out side long xside 40 R2 (fm2) xside xside xside xside xside xside xout xout xout xout xout xout xout 20 K os ol sl 10 K K K K K K 0 -10 0 0 0 180 180 180 No access to 1st-order oscillations in STAR Y1 fp (°) Au+Au 2 AGeV; E895, PLB 496 1 (2000) fp = 0° fp ~45° • Ros2(f) quantifies correlation between xout and xside • No correlation (tilt) b/t between xout and xside at fp=0° (or 90°) • Strong (positive) correlation when fp=45° • Phase of Ros2(f) oscillation reveals orientation of extended source Mike Lisa - XXXII ISMD - Alushta, Ukraine

  16. Indirect indications of x-space anisotropy @ RHIC 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 • 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) Mike Lisa - XXXII ISMD - Alushta, Ukraine STAR, PRL 87 182301 (2001)

  17. STAR data Au+Au 130 GeV minbias full blastwave consistent with R(pT), K-p • significant oscillations observed • blastwave with ~ same parameters as used to describe spectra & v2(pT,m) • additional parameters: • R = 11 fm •  = 2 fm/c !! preliminary Mike Lisa - XXXII ISMD - Alushta, Ukraine

  18. STAR data Au+Au 130 GeV minbias full blastwave no flow anisotropy consistent with R(pT), K-p no spatial anisotropy • significant oscillations observed • blastwave with ~ same parameters as used to describe spectra & v2(pT,m) • additional parameters: • R = 11 fm •  = 2 fm/c !! preliminary • both flow anisotropy and source shape contribute to oscillations, but… • geometry dominates dynamics • freezeout source out-of-plane extended fast freeze-out timescale ! Mike Lisa - XXXII ISMD - Alushta, Ukraine

  19. Azimuthal HBT: hydro predictions • RHIC (T0=340 MeV @ t0=0.6 fm) • Out-of-plane-extended source (but flips with hadronic afterburner) • flow & geometry work together to produce HBT oscillations • oscillations stable with KT (note: RO/RS puzzle persists) Heinz & Kolb, hep-th/0204061 Mike Lisa - XXXII ISMD - Alushta, Ukraine

  20. Azimuthal HBT: hydro predictions • RHIC (T0=340 MeV @ t0=0.6 fm) • Out-of-plane-extended source (but flips with hadronic afterburner) • flow & geometry work together to produce HBT oscillations • oscillations stable with KT • “LHC” (T0=2.0 GeV @ t0=0.1 fm) • In-plane-extended source (!) • HBT oscillations reflect competition between geometry, flow • low KT: geometry • high KT: flow sign flip Heinz & Kolb, hep-th/0204061 Mike Lisa - XXXII ISMD - Alushta, Ukraine

  21. HBT(φ) Results – 200 GeV STAR PRELIMINARY • Oscillations similar to those measured @ 130GeV • 20x more statistics explore systematics in centrality, kT • much more to come… Mike Lisa - XXXII ISMD - Alushta, Ukraine

  22. Summary • Quantitative understanding of bulk dynamics crucial to extracting real physics at RHIC • p-space - measurements well-reproduced by models • anisotropy  system response to compression (EoS) • probe via v2(pT,m) • x-space - generally not well-reproduced • anisotropy  evolution, timescale information, geometry / flow interplay • Azimuthally-sensitive HBT: correlating quantum correlation with bulk correlation • reconstruction of full 3D source geometry • Freezeout geometry out-of-plane extended • early (and fast) particle emission ! • consistent with blast-wave parameterization of v2(pT,m), spectra, R(pT), K-p • With more detailed information, “RHIC HBT puzzle” deepens • what about hadronic rescattering stage? - “must” occur, or…? • does hydro reproduce t or not?? • ~right source shape via oscillations, but misses RL(mT) • Models of bulk dynamics severely (over?)constrained Mike Lisa - XXXII ISMD - Alushta, Ukraine

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