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Flow-Driven Conical Emission in Ultrarelativistic Heavy-Ion Collisions

Flow-Driven Conical Emission in Ultrarelativistic Heavy-Ion Collisions. Barbara Betz Thanks to: Miklos Gyulassy, Jorge Noronha, Dirk Rischke, Giorgio Torrieri. arXiv:1005.5461. The QCD Phase Diagram. proton. Insights into theory of strong interactions (QCD)

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Flow-Driven Conical Emission in Ultrarelativistic Heavy-Ion Collisions

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  1. Flow-Driven Conical Emission inUltrarelativistic Heavy-Ion Collisions Barbara Betz Thanks to: Miklos Gyulassy, Jorge Noronha, Dirk Rischke, Giorgio Torrieri arXiv:1005.5461

  2. The QCD Phase Diagram proton • Insights into theory of strong interactions (QCD) • Medium created in heavy-ion (HIC) collisions similar to the one created after Big Bang • Explore the phase diagram of QCD with HIC FAIR hadronic phase and freeze-out RHIC expanding fireball initial state pre-equilibrium hadronization LHC S. Bass, Talk Quark Matter 2001

  3. The Medium created in a HIC Medium behaves like an almost ideal fluid BNL press release, April 18 2005. • Data described by hydrodynamics • Small • Reproducing the elliptic flow v2 P. Romatschke and U. Romatschke, Phys. Rev. Lett. 99, 172301 (2007) IF the medium behaves like a fluid Particles interact, expansion determined by density gradient

  4. 4 < pTtrigger < 6 GeV/c 0.15 < pTassoc < 4 GeV/c STAR, Nucl. Phys. A 774, 129 (2006) Jet - Studies in HIC I • Mach cones have to occur because of fluid dynamicsRedistribution of energy to lower pT-particles • Mach cone angle sensitive to EoS: H. Stöcker, Nucl. Phys. A 750, 121 (2005), J. Casalderrey-Solana et al. Nucl. Phys. A 774, 577 (2006) Au+Au / p+p = 200 GeV PHENIX, Phys. Rev. C 77, 011901 (2008) Reflect interaction of jet with medium • By observation: • Confirm fast thermalization & Study EoS of the fluid

  5. Jet - Studies in HIC II Position of away-side peaks does not change strongly with pTassoc Not due to Cherenkov gluon radiation What happens to larger pTtrigger? STAR, arXiv: 1004.2377 see also PHENIX, Phys. Rev. C 77, 011901 (2008)

  6. Jet - Studies in HIC III Investigation of path length dependence: Double-peaked structure becomes more pronounced out-of-plane A. Sickeles [PHENIX], Eur. Phys. J. C 61, 583 (2009)

  7. Jet - Studies in HIC IV Centrality dependence: double-peaked structure for central collisions one peak structure for very peripheral collisions PHENIX, Phys. Rev. Lett. 97, 052301 (2006) Energy Scan: double-peaked structure occurs at about the same angle for different collision energies J. Jia, Eur. Phys. J. C 62, 255 (2009)

  8. Modelling Jets using … Diffusion wake Linearized Hydro- dynamics (3+1)d Ideal Hydro J. Casalderrey-Solana et al., Nucl. Phys. A 774, 577 (2006) BB et al., Phys. Rev. C 79, 034902 (2009) Energy density perturbation AdS/CFT pQCD Strongly- coupled theory Weakly- coupled theory v=0.75 v=0.99955 Momentum density perturbation R. Neufeld et al, Phys. Rev. C 78, 041901 (2008) P. Chesler and L. Yaffe, Phys. Rev. D 78, 045013 (2008) Conclusion about Mach cones?

  9. Modelling Jets in Hydrodynamics

  10. STAR, Phys. Rev. Lett. 95, 152301 (2005) • Conversion into particles Freeze-out: Modelling of Jets • Medium created in a HIC can be described using hydrodynamics Jets can be modelled using (ideal) hydrodynamics: residue of energy and momentum given by the jet . e+p v • Assumption of • isochronous/isothermal freeze-out • No interaction afterwards mainly flow driven

  11. Expanding Medium I Experimental results based on many events b=0 Consider different jet paths A. K. Chaudhuri, Phys. Rev. C 75, 057902 (2007) , A. K. Chaudhuri, Phys. Rev. C 77, 027901 (2008) • Apply Glauber initial conditions and an ideal Gas EoS for massless gluons • Focus on radial flow contribution dE/dt = 1 GeV/fm Etot = 5 GeV • Two-particle correlation • (Tfreeze-out < Tcrit = 130 MeV): near-side jet Jet 150

  12. Expanding Medium II BB et al., arXiv: 1005.5461 Etot = 5 GeV pTtrig= 3.5 GeV broad away-side peak double peaked structure due to non-central jets vjet =0.999 PHENIX, Phys. Rev. C 77, 011901 (2008)

  13. Expanding Medium III Etot = 10 GeV pTtrig = 7.5 GeV broad away-side peak double peaked structure Strong impact of the Diffusion wake 6 < pTtrigger < 10 Causes smaller dip for pT=2 GeV Yield 1.5 < pTassoc < 2.5 Path length dependence Centrality dependence STAR, arXiv: 1004.2377 f

  14. Expanding Medium IV Comparing different deposition scenarios, one sees that „cone“ angle approximately the same for different deposition scenarios pTtrig= 3.5 GeV pTassoc= 2.0 GeV pTassoc= 3.0 GeV vjet =0.999 BB et al., arXiv: 1005.5461 pTassoc= 2.0 GeV: No double-peakedstructurefor pure energy depositionscenario due to thermal smearking

  15. Expanding Medium V Considering a bottom quark (M=4.5 GeV), propagating at vjet < cs (on-shell energy-momentum deposition scenario) pTassoc= 2.0 GeV BB et al., arXiv: 1005.5461 PHENIX, PRL98, 232302 (2007) Conical emission angle also appears for subsonic jets Not a Mach cone Cu+Cu: Similaraway-sideshoulderwidth, double-peakstructurereapparsforpTassoc = 3 GeV

  16. Some caveats

  17. ZYAM & Co. • ZYAM (Zero Yield At Minimum): • Can lead to a double-peaked structure • Two-source model: • Can one assume that the correlations • from flow anisotropy and jets are • uncorrelated? D. d’Enterria and BB., Springer Lecture Notes (2008) J. Ulery [STAR], PoS LHC07, 036 (2007) How can one proof/disproof the two-source model? ptrigT=3 – 4 GeV, passocT=1 – 2 GeV • Three-particle correlations seem to corroborate Mach cone idea • What’s the effect of ZYAM? • No agreement with 3-particle cumulant method C. Pruneau, Phys. Rev. C 79, 044907 (2009) J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007)

  18. Some more caveats

  19. Hot Spots I Can fluctuating initial condition explain the 2+3-particle correlations? Takahashi et al, PRL 103, 242301 (2009) R. Andrade et al., arXiv: 0912.0803 F. Grassi, Talk at the Glasma Workshop, BNL, May 2010

  20. Hot Spots II Check with one single hot spot Au, De/e0=0.2 Heavy quark jets are not affected

  21. Fluctuating Initial Conditions

  22. Initial Fluctuations I Glauber initial conditions: due to symmetry, odd Fourier components vanish Fluctuating initial conditions: B. Alver, , Talk at the Glasma Workshop, BNL, May 2010 higher Fourier components may occur P. Sorensen, arXiv:1002.4878, B. Alver et al., Phys. Rev. C 81, 054905 (2010)

  23. Initial Fluctuations II • v3 is extensively studied B. Alver et al., Phys. Rev. C 81, 054905 (2010) , B. Alver et al., arXiv: 1007.5469 H. Petersen et al., arXiv: 1008.0625 B. Alver et al., arXiv: 1007.5469 Calculating v3 using a viscous hydro model with initial conditions deformed according to the eccentricities from a Glauber and a KLM (CGC) model v3 not negligable small

  24. Initial Fluctuations III • Correlation in Df1-Df2 • Df1/2 120° • No correlation in Dh1-Dh2 What are the consequences of triangular flow? 120° B. Alver et al., Phys. Rev. C 81, 054905 (2010) 3 < pTtrig < 10GeV, 1 < pTassoc < 3GeV 0-12% Au+Au J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007) ptrigT=3 – 4 GeV, passocT=1 – 2 GeV B. Abelev et al. (STAR), arXiv: 0912.2977 Do we only see fluctuating initial conditions? What is the difference of v3 and the impact of hot spots? Study of heavy quark jets needed

  25. Summary • „Conical“ signal can be created (general effect): by averaging over wakes created by jets in different events. There is a deflection of particles emitted due to collective transverse flow. Quite insensitive to deposition mechanism, jet velocity (even for subsonic jets), and system size Structure cannot directly be related to EoS, but is a measure for the flow • Measuredaway-sidestructuremaybe due toinitialfluctuations Mach coneshavetooccur in heavy-ioncollisionsifthereis a fluid Necessary to study heavy-flavor tagged jets.

  26. Backup

  27. 4 < pTtrigger < 6 GeV/c pTassoc > 2 GeV/c STAR, Phys. Rev. Lett. 91 (2003) 072304 Probing Matter • Like in medicine, hard probes can be used to investigate the medium properties • If created matter is opaque, a jet depositing its energy should eventually disappear jet suppression University Wuppertal, “Schul-Vorlesungen zur Physik” Trigger particle What can the energy lost tell us about the medium properties?

  28. Initial Fluctuations pTtrig > 2.5 GeV, pTassoc > 1.0 GeV Takahashi et al, PRL 103, 242301 (2009) 0-10% Au+Au, v2 ZYAM subtracted Fluctuating initial conditions (NEXUS) also lead to a ridge structure 0-30% Au+Au PHOBOS, J. Phys. G 35, 104080 (2008) v2 correlations also extend out to Dh > 2

  29. Punch-Through Jet

  30. Punch – Through Jet I Applying a static medium and an ideal Gas EoS for massless gluons Maximal fluid response Assume: Near-side jet is not modified by medium BB et al., Phys. Rev. C 79, 034902 (2009) v=0.999 t=4.5/v fm

  31. Punch – Through Jet II BB et al., Phys. Rev. C 79, 034902 (2009) Normalized, background-subtracted isochronous Cooper-Frye at mid-rapidity pT = 5 GeV Energy Flow Distribution Diffusion wake causes peak in jet direction Assuming: Particles in subvolume will be emitted into the same direction

  32. Punch – Through Jet III BB et al., Phys. Rev. C 79, 034902 (2009) Does the jet-pattern reproduce the features of a Mach cone? pT = 5 GeV Velocity dependence of the emission angle Creation of Bow Shock for smaller v strengthens peak in jet direction

  33. Punch – Through Jet IV • Transverse momentum deposition: t=4.5/v fm BB et al., Phys. Rev. C 79, 034902 (2009) Still influence of diffusion wake from explosion of matter Vorticity conservation

  34. Punch – Through vs Stopped BB et al., Phys. Rev. C 79, 034902 (2009) pT = 5 GeV pT = 5 GeV Punch-Through Jet Stopped Jet Similar freeze-out patterns

  35. The Static Medium

  36. Stopped Jet I Applying a static medium and an ideal Gas EoS for massless gluons Maximal fluid response Assume: Near-side jet is not modified by medium BB et al., Phys. Rev. C 79, 034902 (2009) Jet decelerating from v=0.999 according to Bethe-Bloch formalism Bragg Peak a=-1.36 GeV/fm adjusts path length Simplest back-reaction from the medium

  37. Stopped Jet II t=4.5/v fm BB et al., Phys. Rev. C 79, 034902 (2009) Mach cone for sound waves Diffusion wake

  38. Stopped Jet III BB et al., Phys. Rev. C 79, 034902 (2009) Normalized, background-subtracted isochronous Cooper-Frye at mid-rapidity pT = 5 GeV Energy Flow Distribution Assuming: Particles in subvolume will be emitted into the same direction Diffusion wake causes peak in jet direction Any conclusions about deposition mechanism???

  39. Stopped Jet IV • Jet stops after t=4.5/v fm BB et al., Phys. Rev. C 79, 034902 (2009) tFO=4.5/v fm tFO=6.5/v fm tFO=8.5/v fm Diffusion wake still present Vorticity conservation

  40. Stopped Jet V Larger impact of thermal smearing Diffusion wake causes peak in jet direction BB et al., Phys. Rev. C 79, 034902 (2009) tFO=4.5/v fm tFO=6.5/v fm tFO=8.5/v fm

  41. Different Jet-Energy Loss Modells

  42. Mach cone in coordinate space Jets in pQCD I Considering a static medium and linearized hydrodynamics for a punch-though jet R. Neufeld et al, Phys. Rev. C 78, 041901 (2008) Signal dissolves with viscosity R. Neufeld et al., Phys. Rev. C 79, 054909 (2009)

  43. Jets in pQCD II Crescendo Deposition Scenario1 can lead to a double-peaked structure, depending on l2 and h/s 1Increasing number of radiated gluons deposit energy Ep >> DEtot 2local medium excitation parameter Static medium R. Neufeld and T. Renk, arXiv:1001.5068. Likewise, a jet shower can result in a double- peaked away-side H. Li et al., arXiv: 1006.2893. Deflection due to background flow and averaging matters and can lead to the double-peaked away-side structure depending on cross-section H. Li et al., arXiv: 1006.2893.

  44. Jets in AdS/CFT Non-Mach correlations caused by Neck region J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009)

  45. Heavy Quark Jets Compare weakly and strongly coupled models using heavy punch-through jet Static medium and isochronous freeze-out needed for comparison BB et al., Phys. Lett. B 675, 340 (2009) pQCD: Neufeld et al. source for a heavy quark R. Neufeld et al, Phys. Rev. C 78, 041901 (2008) AdS/CFT: Stress tables with S. Gubser et al, Phys. Rev. Lett. 100, 012301 (2008) t=4.5/v fm J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009) BB et al., Phys. Lett. B 675, 340 (2009) No Mach-like peaks: AdS/CFT: Strong influence of the Neck region pT = 3.14 GeV

  46. The Expanding Medium

  47. Satarov et al, PLB 627:64 (2005) Expanding Medium • Consequences of expansion? Radial flow, Elliptic flow • Predictions: Transverse flow causes distortion Expansion broadens Mach cone angle Mach cones are sensitive to the background flow • Qualitative, model-independent effect

  48. Expanding Medium Jet 90 Jet 120 Jet 180 Jet 150

  49. Expanding Medium Etot = 5 GeV pTtrig = 3.5 GeV broad away-side peak broad away-side peak Pure energy deposition No conical distribution in expanding medium for pT=1 GeV and pT=2 GeV Jet 180: No peaks on away-side

  50. Expanding Medium Etot = 5 GeV pTtrig = 3.5 GeV broad away-side peak double peaked structure Pure momentum deposition The same pT-dependence as for energy and momentum deposition

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