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Conjectured Phase Diagram

Acoustic scaling of anisotropic flow in shape-engineered events : implications for extraction ( μ B ,T) of the QGP Roy A. Lacey Stony Brook University. p. A Current Focus of our Field. Quantitative study of the QCD phase diagram. Conjectured Phase Diagram. Interest

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Conjectured Phase Diagram

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  1. Acoustic scaling of anisotropic flow in shape-engineered events: implications for extraction (μB,T) of the QGP Roy A. Lacey Stony Brook University Roy A. Lacey, Stony Brook University, April 24th, 2014

  2. p A Current Focus of our Field Quantitative study of the QCD phase diagram Conjectured Phase Diagram • Interest • Location of the critical End point (CEP) • Location of phase coexistence lines • Properties of each phase • All are fundamental to the phase diagram of any substance Spectacular achievement: Validation of the crossover transition leading to the QGP  Necessary for the CEP? Extraction of the ()-dependence of transport coefficients is central to the heavy ion programs at RHIC and the LHC Roy A. Lacey, Stony Brook University, April 24th, 2014

  3. Current Strategy Exploit system size and beam energy lever arm (,T) at freeze-out Energy scan • LHC  access to high T and small • RHICaccess to different systems and • a broad domain of the (,T)-plane • LHC + BES  access to an even broader domain of the (,T)-plane RHICBES to LHC  360 increase Roy A. Lacey, Stony Brook University, April 24th, 2014

  4. Essential Questions Lacey et. al, arXiv:0708.3512(2008) Lacey et. al, Phys.Rev.Lett.98:092301 (2007) • ()-dependence of transport • coefficients , , etc? • The role of system size and • fluctuations? • Location of phase boundaries? • Indications for a Critical End • Point (CEP)? At the CEP or close to it, anomalies in the dynamic properties of the medium can drive abrupt changes in transport coefficients Anisotropic flow is an invaluable probe Roy A. Lacey, Stony Brook University, April 24th, 2014

  5. Reminder Subsequently (η/s)RHICestimates – QM2009 • Excellent Convergence on • the magnitude of η/s at RHIC 4πη/s ~ 1 - 2 • T dependence of η/s? • μB dependence of η/s? • Possible signal for CEP? Status Quo A major uncertainty in the extraction of η/s stems from Incomplete knowledge of the Initial-state eccentricity model εn – η/s interplay? Roy A. Lacey, Stony Brook University, April 24th, 2014

  6. Status Quo Luzum et al. arXiv 0804.4015 Song et al Status Quo A major uncertainty in the extraction of η/s stems from Incomplete knowledge of the Initial eccentricity? εn – η/s interplay? 15-20% ε2difference 2x η/s difference η/s is a property of the medium and should not depend on initial geometry! This is NOT an uncertainty; It is a failure of the method of extraction New methodology and constraints required Roy A. Lacey, Stony Brook University, April 24th, 2014

  7. Improved Methodology BjoernSchenke et. al. arXiv:1301.5893 4πη/s for LHC plasma ~ 2 Higher harmonics provide important constraints! Can we find methodologies and constraints which are insensitive to the initial-state geometry? Roy A. Lacey, Stony Brook University, April 24th, 2014

  8. Essential message • The acoustic nature of flow leads to specific scaling patterns which : • Give profound mechanistic insight on viscous damping • Provide constraints for • initial state geometry and its fluctuations • Extraction of the specific viscosity • (,T) dependence of the viscous coefficients • Hints for a possible critical point?  Significant and important recent development in the field! Roy A. Lacey, Stony Brook University, April 24th, 2014

  9. The Flow Probe Anisotropic p Idealized Geometry Isotropic p Yield(f) =2 v2cos[2(f-Y2] Crucial parameters Actual collision profiles are not smooth, due to fluctuations! Initial Geometry characterized by many shape harmonics (εn)  drive vn Acoustic viscous modulation of vn Staig & ShuryakarXiv:1008.3139 Initial eccentricity (and its attendant fluctuations) εndrive momentum anisotropy vnwith specific viscous modulation Roy A. Lacey, Stony Brook University, April 24th, 2014

  10. Scaling properties of flow Initial Geometry characterized by many shape harmonics (εn)  drive vn Acoustic viscous modulation of vn Staig & ShuryakarXiv:1008.3139 Scaling expectations: n2 dependence vn is related to v2 System size dependence Each of these scaling expectations can been validated η/s , ’ Roy A. Lacey, Stony Brook University, April 24th, 2014

  11. Demonstration of acoustic scaling • What do we learn from these scaling patterns? Roy A. Lacey, Stony Brook University, April 24th, 2014

  12. Geometric quantities for scaling Geometry Phys. Rev. C 81, 061901(R) (2010) B A arXiv:1203.3605 σx & σy RMS widths of density distribution • Geometric fluctuations included • Geometric quantities constrained by multiplicity density. Roy A. Lacey, Stony Brook University, April 24th, 2014

  13. Relationship between initial and freeze-out geometry Femtoscopic measurements • R and mT scaling of the full set of HBT data • Similar expansion dynamics • Larger expansion rates at the LHC • exquisitely demonstrated via HBT measurement Roy A. Lacey, Stony Brook University, April 24th, 2014

  14. Relationship between initial and freeze-out geometry Femtoscopic measurements arXiv:1404.5291 • Larger expansion • rate at the LHC • exquisitely demonstrated via HBT measurement for several systems Roy A. Lacey, Stony Brook University, April 24th, 2014

  15. Scaling properties of flow Acoustic Scaling – Centrality 5-70% • Eccentricity change alone is not sufficient • To account for the Npart dependence of vn • Transverse size () influences viscous damping • Characteristic scaling prediction is • non-trivial Roy A. Lacey, Stony Brook University, April 24th, 2014

  16. Scaling properties of flow Acoustic Scaling – • Characteristic viscous damping validated • at RHIC & the LHC • A further constraint for η/s Roy A. Lacey, Stony Brook University, April 24th, 2014

  17. Scaling properties of flow - Viscous Hydrodynamics • Characteristic a • The relative magnitude of • vn provides an important • constraint! • η/s • Viscous hydrodynamics can be used for calibration Roy A. Lacey, Stony Brook University, April 24th, 2014

  18. Shape-engineered events Shape fluctuations lead to a distribution of the Q vector at a fixed centrality • Cuts on qn should change the magnitudes ,, at a given centrality due to fluctuations • These magnitudes can influence scaling • Note characteristic anti-correlation predicted for v3(q2) in mid-central events • Crucial constraint for initial-geometry models Roy A. Lacey, Stony Brook University, April 24th, 2014

  19. Shape-engineered events ALICE data Shape fluctuations lead to a distribution of the Q vector at a fixed centrality q2(Hi) • Cuts on qn should change the magnitudes ,, at a given centrality due to fluctuations q2(Lo) • Viable models for initial-state fluctuations should still scale Roy A. Lacey, Stony Brook University, April 24th, 2014

  20. Scaling properties of flow Acoustic Scaling of shape-engineered events • Characteristic viscous damping validated • for different event shapes at the same centrality • A further constraint for initial fluctuations model and η/s Roy A. Lacey, Stony Brook University, April 24th, 2014

  21. Extraction of η/s Song et al • η/s show 100% uncertainty due to “uncertainty” about the • initial geometry • η/s is a property of the medium and should not depend on initial • geometry • This is NOT an uncertainty; It is an incorrect method of extraction Slope sensitive to 4η/s Characteristic viscous damping validated in viscous hydrodynamics;calibration  4πη/s ~ Extracted η/s value insensitive to initial conditions Roy A. Lacey, Stony Brook University, April 24th, 2014

  22. Extraction of η/s arXiv:1301.0165 & CMS PAS HIN-12-011 Viscous Hydro Slope sensitive to η/s n2 scaling validated in experiment and viscous hydrodynamics; calibration  4πη/s ~ 2 Note agreement with Schenke et al. Roy A. Lacey, Stony Brook University, April 24th, 2014

  23. Anisotropy Measurements arXiv:1305.3341 CMS - Phys.Rev.C87, 014902 (2013) STAR - Phys.Rev.C86, 014904 (2012); Phys.Rev.C86, 054908 (2012) • An extensive set of measurements now span a broad range of beam energies (). Roy A. Lacey, Stony Brook University, April 24th, 2014

  24. Scaling properties of flow Lacey et. al. Phys. Rev. Lett. 112, 082302 Acoustic Scaling – 200 GeV 7.7 GeV 19.6 GeV 39 GeV 62.4 GeV 2.76 TeV • Characteristic viscous damping validated across beam energies • First experimental indication for η/s variation in the -plane HBT should show complimentary signals for similar Roy A. Lacey, Stony Brook University, April 24th, 2014

  25. Summary Scaling properties of anisotropic flow lend profound mechanistic insights, as well as new constraints for transport coefficients What do we learn? • Flow is acoustic – “as it should be” • Obeys the dispersion relation for sound propagation • (n2& )  constraints for 4πη/s & viable initial-state models • 4πη/s for RHIC plasma ~ 1~ my 2006 estimate • 4πη/s for LHC plasma ~ 2 • Extraction insensitive to initial geometry model • Characteristic dependence of viscous coefficient β” on beam energy give constraints for: • ()-dependenceη/s • Indication for CEP?? Roy A. Lacey, Stony Brook University, April 24th, 2014

  26. End Roy A. Lacey, Stony Brook University, April 24th, 2014

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