1. Conical Correlations in Heavy-Ion Collisions Barbara Betz Thanks to: Miklos Gyulassy, Jorge Noronha, Dirk Rischke, Giorgio Torrieri Phys. Rev. C 79, 034902 (2009), Phys. Lett. B 675, 340 (2009), Nucl. Phys. A 830, 777c (2009), arXiv:1005.5461

2. 209/13/10 MIT Seminar, Boston Barbara Betz Conical Correlations in HIC What are conical correlations in heavy-ion collisions? Correlations revealing the creation of Mach cones??? Experiment: Review on experimental studies Conclusions and Outlook Theoretical approaches: Jets & hydrodynamics Different energy-loss mechanisms What could they tell us about the medium created? Fluctuating initial conditions, v 3 (carrying coals to Newcastle) Why we need to study heavy-flavor tagged jets Deflection of wakes due to transverse flow Conical signal

3. 3 HIC Facilities initial state pre-equilibrium expanding fireball hadronization hadronic phase and freeze-out S. Bass, Talk Quark Matter 2001 RHIC FAIR LHC 09/13/10 MIT Seminar, Boston Barbara Betz RHIC, BNL: 2000 – … p+p, d+Au, Cu+Cu, Au+Au LHC, CERN: 2008/9 - … p+p, Pb+Pb FAIR, GSI: ~2016 - … accelerates ions from p to U

4. 4 2 Major RHIC Results 09/13/10 MIT Seminar, Boston Barbara Betz

5. 5 Reproducing the elliptic flow v 2 P. Romatschke and U. Romatschke, Phys. Rev. Lett. 99, 172301 (2007) Medium behaves like an almost ideal fluid BNL press release, April 18 2005. 09/13/10 MIT Seminar, Boston Barbara Betz Particles dont interact, expansion independent of initial shape Particles interact, expansion determined by density gradient dust fluid Data can be described by hydrodynamics with small Fluid-like Medium

6. 6 Jet Quenching 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 STAR, Phys. Rev. Lett. 91 (2003) 072304 4 < p T trigger < 6 GeV/c p T assoc > 2 GeV/c What can the energy lost tell us about the medium properties? Trigger particle University Wuppertal, Schul-Vorlesungen zur Physik 09/13/10 MIT Seminar, Boston Barbara Betz

7. 7 Jets in HIC I By observation: Confirm fast thermalization Study EoS of the fluid Mach cone angle sensitive to EoS Can energy lost by jets tell us something about medium properties? IF the medium behaves like a fluid: Mach cones have to occur because of fluid dynamics

8. 4 < p T trigger < 6 GeV/c 0.15 < p T assoc < 4 GeV/c Au+Au / p+p = 200 GeV PHENIX, Phys. Rev. C 77, 011901 (2008) 8 Jets in HIC II STAR, Nucl. Phys. A 774, 129 (2006) Reflect interaction of jet with medium Redistribution of energy to lower p T - particles Re-appearance of the away-side for low and intermediate p T assoc H. Stöcker, Nucl. Phys. A 750, 121 (2005), J. Casalderrey-Solana et al. Nucl. Phys. A 774, 577 (2006) 09/13/10 MIT Seminar, Boston Barbara Betz

9. 9 Experimental Studies 09/13/10 MIT Seminar, Boston Barbara Betz

10. 10 STAR, Phys. Rev. C 82, 024912 (2010) see also PHENIX, Phys. Rev. C 77, 011901 (2008) Position of away-side peaks does not change strongly with p T assoc Not due to Cherenkov gluon radiation What happens to larger p T trigger ? Jet - Studies in HIC I 09/13/10 MIT Seminar, Boston Barbara Betz

11. 11 Investigation of path length dependence: Double-peaked structure becomes more pronounced out-of-plane A. Sickeles [PHENIX], Eur. Phys. J. C 61, 583 (2009) Jet - Studies in HIC II 09/13/10 MIT Seminar, Boston Barbara Betz Could be due to deflection

12. 12 Centrality dependence: double-peaked structure for central collisions one peak structure for very peripheral collisions PHENIX, Phys. Rev. Lett. 97, 052301 (2006) J. Jia, Eur. Phys. J. C 62, 255 (2009) Jet - Studies in HIC III Energy Scan: double-peaked structure occurs at about the same angle for different collision energies Mach cone??? 09/13/10 MIT Seminar, Boston Barbara Betz

13. 13 Some caveats 09/13/10 MIT Seminar, Boston Barbara Betz

14. 14 Background Subtraction How can one proof/disproof the two-source model? J. Ulery [STAR], PoS LHC07, 036 (2007) D. dEnterria and BB., Springer Lecture Notes (2008) 09/13/10 MIT Seminar, Boston Barbara Betz Assumption (Two-source model) : No correlations between flow anisotropy and jets ZYAM (Zero Yield At Minimum) Subtraction of: estimated elliptic flow modulated background can leads to: double peaked structure Background: Particle correlation from elliptic flow

15. 15 3-Particle Correlations J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007) p trig T =3 – 4 GeV, p assoc T =1 – 2 GeV Three-particle correlations seem to corroborate Mach cone idea Whats the effect of ZYAM? No agreement with 3-particle cumulant method C. Pruneau, Phys. Rev. C 79, 044907 (2009) 09/13/10 MIT Seminar, Boston Barbara Betz Deflected jetMach Cone p trig T >3 GeV, p assoc T =1 – 2 GeV C. Pruneau, Talk at the Workshop on Critical Asessment of Theory and Experiment on Correlations at RHIC, BNL, February 2009

16. 16 Theoretical Approach 09/13/10 MIT Seminar, Boston Barbara Betz

17. 17 Modelling of Jets STAR, Phys. Rev. Lett. 95, 152301 (2005) residue of energy and momentum given by the jet Assumption of isochronous/isothermal freeze-out No interaction afterwards mainly flow driven Conversion into particles Freeze-out: Jets can be modelled using (ideal) hydrodynamics: e +p v. Medium created in a HIC can be described using hydrodynamics 09/13/10 MIT Seminar, Boston Barbara Betz

18. 18 The Static Medium 09/13/10 MIT Seminar, Boston Barbara Betz

19. 19 Stopped Jet I Applying a static medium and an ideal Gas EoS for massless gluons Assume: Near-side jet is not modified by medium Maximal fluid response Jet decelerating from v=0.999 according to Bethe-Bloch formalism a=-1.36 GeV/fm Simplest back-reaction from the medium Bragg Peak adjusts path length BB et al., Phys. Rev. C 79, 034902 (2009) 09/13/10 MIT Seminar, Boston Barbara Betz

20. 20 Stopped Jet II Mach cone for sound waves Diffusion wake t=4.5/v fm BB et al., Phys. Rev. C 79, 034902 (2009) 09/13/10 MIT Seminar, Boston Barbara Betz

21. 21 Stopped Jet III Diffusion wake causes peak in jet direction Normalized, background-subtracted isochronous Cooper-Frye at mid-rapidity Energy Flow Distribution Assuming: Particles in subvolume will be emitted into the same direction p T = 5 GeV BB et al., Phys. Rev. C 79, 034902 (2009) Any conclusions about deposition mechanism??? 09/13/10 MIT Seminar, Boston Barbara Betz

22. 22 Stopped Jet IV Jet stops after t=4.5/v fm Vorticity conservation t FO =4.5/v fmt FO =6.5/v fmt FO =8.5/v fm Diffusion wake still present BB et al., Phys. Rev. C 79, 034902 (2009) 09/13/10 MIT Seminar, Boston Barbara Betz

23. 23 Stopped Jet V t FO =4.5/v fmt FO =6.5/v fmt FO =8.5/v fm Diffusion wake causes peak in jet direction Larger impact of thermal smearing BB et al., Phys. Rev. C 79, 034902 (2009) 09/13/10 MIT Seminar, Boston Barbara Betz

24. 24 A Comparison 09/13/10 MIT Seminar, Boston Barbara Betz

25. 25 BAMPS: Boltzmann Approach of MultiParton Scatterings A transport algorithm solving the Boltzmann equations for on-shell partons with pQCD interactions C. Greiner, Talk at the Opening Symposium of the JET Collaboration, Berkeley, June 2010 Box scenario, no expansion, massless Boltzmann gas interactions, 2 -> 2 The shock front (Mach front) gets broader and vanish with more dissipation 09/13/10 MIT Seminar, Boston Barbara Betz Mach Cones in Transport

26. 2609/13/10 MIT Seminar, Boston Barbara Betz Different Jet-Energy Loss Modells

27. 2709/13/10 MIT Seminar, Boston Barbara Betz Modelling Jets using … Conclusion about Mach cones? pQCD AdS/CFT P. Chesler and L. Yaffe, Phys. Rev. D 78, 045013 (2008) R. Neufeld et al, Phys. Rev. C 78, 041901 (2008) Strongly-coupled theory Pointing vector perturbation Momentum density perturbationEnergy density perturbation Weakly-coupled theory v=0.75 v=0.99955

28. 2809/13/10 MIT Seminar, Boston Barbara Betz Non-Mach correlations caused by Neck region Jets in AdS/CFT J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009)

29. 2909/13/10 MIT Seminar, Boston Barbara Betz Heavy Quark Jets

30. 3009/13/10 MIT Seminar, Boston Barbara Betz Heavy Quark Jets Compare weakly and strongly coupled models using heavy punch-through jet pQCD: Neufeld et al. source for a heavy quark AdS/CFT: Stress tables with R. Neufeld et al, Phys. Rev. C 78, 041901 (2008) p T = 3.14 GeV BB et al., Phys. Lett. B 675, 340 (2009) No Mach-like peaks: AdS/CFT: Strong influence of the Neck region Static medium and isochronous freeze-out needed for comparison t=4.5/v fm S. Gubser et al, Phys. Rev. Lett. 100, 012301 (2008) BB et al., Phys. Lett. B 675, 340 (2009) J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009)

31. 3109/13/10 MIT Seminar, Boston Barbara Betz The Expanding Medium

32. 32 Expanding Medium I Consider different jet paths b=0 Apply Glauber initial conditions and an ideal Gas EoS for massless gluons Focus on radial flow contribution Experimental results based on many events A. K. Chaudhuri, Phys. Rev. C 75, 057902 (2007), A. K. Chaudhuri, Phys. Rev. C 77, 027901 (2008) Two-particle correlation (T freeze-out < T crit = 130 MeV): near-side jet dE/dt = 1 GeV/fm Jet 150 E tot = 5 GeV 09/13/10 MIT Seminar, Boston Barbara Betz

33. 33 Expanding Medium II E tot = 5 GeV broad away-side peak double peaked structure due to non-central jets T trig p T trig = 3.5 GeV PHENIX, Phys. Rev. C 77, 011901 (2008) v jet =0.999 BB et al., arXiv: 1005.5461 09/13/10 MIT Seminar, Boston Barbara Betz

34. 34 Expanding Medium III E tot = 10 GeV Strong impact of the Diffusion wake broad away-side peak double peaked structure Causes smaller dip for p T =2 GeV T trig p T trig = 7.5 GeV 6 < p T trigger < 10 1.5 < p T assoc < 2.5 Yield Path length dependence Centrality dependence 09/13/10 MIT Seminar, Boston Barbara Betz STAR, Phys. Rev. C 82, 024912 (2010)

35. 35 Expanding Medium IV Comparing different deposition scenarios, one sees that cone angle approximately the same for different deposition scenarios T assoc p T assoc = 2.0 GeV: No double-peaked structure for pure energy deposition scenario due to thermal smearking T trig p T trig = 3.5 GeV T assoc p T assoc = 3.0 GeV T assoc p T assoc = 2.0 GeV v jet =0.999 BB et al., arXiv: 1005.5461 09/13/10 MIT Seminar, Boston Barbara Betz

36. 36 Expanding Medium V Conical emission angle also appears for subsonic jets Not a Mach cone Considering a bottom quark (M=4.5 GeV), propagating at v jet < c s (on-shell energy-momentum deposition scenario) T assoc p T assoc = 2.0 GeV Cu+Cu: Similar away-side shoulder width, T assoc double-peak structure reappars for p T assoc = 3 GeV BB et al., arXiv: 1005.5461 PHENIX, PRL98, 232302 (2007) 09/13/10 MIT Seminar, Boston Barbara Betz

37. 37 Some more caveats 09/13/10 MIT Seminar, Boston Barbara Betz

38. 38 Hot Spots I Can fluctuating initial condition explain the 2+3-particle correlations? Takahashi et al, PRL 103, 242301 (2009) F. Grassi, Talk at the Glasma Workshop, BNL, May 2010 R. Andrade et al., arXiv: 0912.0803 09/13/10 MIT Seminar, Boston Barbara Betz

39. 39 Hot Spots II Check with one single hot spot Heavy quark jets are not affected 09/13/10 MIT Seminar, Boston Barbara Betz Au, e/e 0 =0.2

40. 40 Fluctuating Initial Conditions 09/13/10 MIT Seminar, Boston Barbara Betz

41. 41 Initial Fluctuations I P. Sorensen J. Phys. G 37, 094011 (2010), B. Alver et al., Phys. Rev. C 81, 054905 (2010) Glauber initial conditions: due to symmetry, odd Fourier components vanish higher Fourier components may occur Fluctuating initial conditions: B. Alver, Talk at the Glasma Workshop, BNL, May 2010 09/13/10 MIT Seminar, Boston Barbara Betz

42. 42 Initial Fluctuations II B. Alver et al., arXiv: 1007.5469 B. Alver et al., Phys. Rev. C 81, 054905 (2010), B. Alver et al., arXiv: 1007.5469 H. Petersen et al., arXiv: 1008.0625 v 3 not negligable small v 3 is extensively studied Calculating v 3 using a viscous hydro model with initial conditions deformed according to the eccentricities from a Glauber and a KLM (CGC) model 09/13/10 MIT Seminar, Boston Barbara Betz

43. 43 Why v 3 deformations cannot be the whole story p trig T =3 – 4 GeV, p assoc T =1 – 2 GeV What are the consequences of triangular flow? Do we only see fluctuating initial conditions? What is the difference of v 3 and the impact of hot spots? Study of heavy quark jets needed 120° 09/13/10 MIT Seminar, Boston Barbara Betz Correlation in 1 - 2 1/2 120° No correlation in 1 - 2 B. Alver et al., Phys. Rev. C 81, 054905 (2010) Shock front?? ~ 120 J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007)

44. 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. Structure cannot directly be related to EoS, but is a measure for the flow Quite insensitive to deposition mechanism, jet velocity (even for subsonic jets), and system size Necessary to study heavy-flavor tagged jets. 44 Conical correlations could arise from multiple non-Mach sources Mach cones have to occur in heavy-ion collisions if there is a fluid 09/13/10 MIT Seminar, Boston Barbara Betz