1 / 54

Christoph Blume University of Heidelberg

International School on: Quark-Gluon Plasma and Heavy Ion Collisions: Past, Present, Future Villa Gualino, Turino, Italy Soft Probes II. Christoph Blume University of Heidelberg. Observables. Temperature. Strangeness Resonances. Femtoscopy Fluctuations. Kinetic Freeze-Out.

holly
Download Presentation

Christoph Blume University of Heidelberg

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. International School on:Quark-Gluon Plasma and Heavy Ion Collisions:Past, Present, FutureVilla Gualino, Turino, ItalySoft Probes II Christoph Blume University of Heidelberg

  2. Observables Temperature Strangeness Resonances Femtoscopy Fluctuations Kinetic Freeze-Out Chemical Freeze-Out Flow Jets + Heavy Flavor Photons

  3. Strangeness

  4. Strangeness in Heavy Ion Physics Strangeness enhancement as a QGP signature J. Rafelski and B. Müller, PRL48, 1066 (1982) P. Koch, B. Müller, and J. Rafelski, Phys. Rep. 142, 167 (1986) Strangeness has to be produced (no s-Quarks in nucleons) Thresholds are high in hadronic reactions, e.g..: N + N  N + K+ +  (Ethres  700 MeV) Fast equilibration in a QGP via partonic processes, e.g. gluon-fusion ⇒ Enhancement of strange particle production in A+A relative to p+p expected (in particular multi-strange particles)

  5. Statistical Models Multiplicities determined by statistical weights (⇒ chemical equilibrium) Grand-canonical partition function: ⇒ Parameters: V, T, μB, γS Details: see F. Becattini’s lecture A.Andronic et al. PLB673, 142 (2009) F.Becattini et al., PRC69, 024905 (2004)

  6. Pb+Pb@ √sNN = 17.3 GeV UrQMD Hadronic Transport Models Microscopic approach Hadronic degrees of freedom Non-equilibrium Production mechanisms: Measured and parameterized cross sections String-excitation and fragmentation Medium effects, Multi-meson fusion, Mass shifts, ... Examples: UrQMD HSD NEXUS (AMPT) (EPOS) ...

  7. Strange Particles

  8. Strangeness Conservation  s s = Isospin Symmetry  Isospin Symmetry    K+ (us) K- (us) K0 (ds)  (uds) K0 (ds) Major Strangeness Carriers: Kaons and Lambdas  >> >>  (uds)  If baryon density is high

  9. Measurement of Charged Kaons via dE/dx Bethe-Bloch function:

  10. Combination of dE/dx and Time-Of-Flight (TOF)

  11. Weak Decay Topologies V0 Topology (K0s, Λ): Ξ- (Cascade) Ω- Topology:

  12. p + -  - K0 - Strangeness Production in a Pion-Proton Event Associated production:

  13. Strangeness Production in a Heavy Ion Event

  14. Reconstruction via Decay Topology NA49 NA57 NA57

  15. Armenteros-Podolanski Plot

  16. Strangeness Enhancement (SPS) NA57: JPG32, 427 (2006)

  17. Strangeness Enhancement (RHIC) STAR: PRC77, 044908 (2008)

  18. Enhancement Towards Lower Energies √sNN (GeV) Contrary to naive expectation Same behavior for multi-strange particles?

  19. Particle Ratios in p+p: RHIC and LHC Increase of relative strangeness production in p+p with √s ALICE: arXiv:1012.3257

  20. Ξ at Threshold Energies Expectation for statistical model (Andronic et al.) HADES: PRL103, 132301 (2009)

  21. Strangeness Enhancement as QGP Signature ? Is it a dominantly partonic effect or can hadronic processes lead to the same fast equilibration? Multi-meson fusion processes C. Greiner and S. Leupold, J. Phys. G 27, L95 (2001) Dynamic equilibration at the phase boundary? P. Braun-Munzinger, J. Stachel, and C. Wetterich, Phys. Lett. B 596, 61 (2004) Hadronization generally a statistical phenomenon? U. Heinz, Nucl. Phys. A 638, 357c (1998), R. Stock, Phys. Lett. B 456, 277 (1999)

  22. Energy Dependence of K/π Ratios Quite sharp maximum in K+/π+ ratio Indication for phase transition (?) PRC77, 024903 (2008) arXiv:1007.2613

  23. − / +/ Energy Dependence of Hyperon/π Ratios |y| < 0.4 / -/  = 1.5 (+ + -) |y| < 0.5 PRC78, 034918 (2008)

  24. Maximum of Relative Strangeness Production

  25. Chemical Freeze-Out Curve

  26. Chemical Freeze-Out in the QCD Phase Diagram

  27. Spectra

  28. Rapidity Distributions ... BRAHMS: Au+Au, √sNN = 200 GeV

  29. Landau ... p+p Data Pion production ~ Entropy Isentropic expansion Description of the pion gas as a 3D relativistic fluid Prediction: dN/dy is Gaussian of a width given by: L. D. Landau, Izv. Akad. Nauk. SSSR 17 (1953) 52 P. Carruthers and M. Duong-Van, PRD8 (1973) 859

  30. Landau ... works also for Heavy Ions BRAHMS: PRL94, 162301 (2005)

  31. Width of the Φ Rapidity Distribution Expectation for kaon coalescence K+ + K- → Φ PRC78, 044907 (2008)

  32. Radial Expansion and Transverse Momentum Spectra 1/mT dN/dmT 1/mT dN/dmT mT mT No radial flow: exponential spectrum (p+p collisions) With radial flow: add. boost by expansion (vT) ⇒ blue shifted spectrum

  33. Blast Wave Analysis of Particle Spectra Central Pb+Pb 158A GeV E. Schnedermann and U. Heinz, PRC50, 1675 (1994)

  34. Energy Dependence of Kinetic Freeze-Out arXiv:1007.2613

  35. Energy Dependence of 〈mT〉 NA49: PRC77, 024903 (2008)

  36. Radial Expansion of Strange Particles What about heavy particles (Ξ, Ω, J/ψ) ? NA57: JPG32, 2065 (2006)

  37. Radial Expansion of Strange Particles Particles with low hadronic cross sections: Ξ, Ω, J/ψ ⇒ Not sensitive to flow in hadronic, but maybe to partonic phase N. Xu and M. Kaneta, NPA698, 306 (2002) 306.

  38. Radial Expansion of Strange Particles Multi-strange particles sensitive to the partonic flow contribution (?) STAR: PRL92, 182301 (2004)

  39. Resonances

  40. Resonances Strong decays ⇒ short lifetimes that can be in the order of the fireball lifetime Examples: K(892) → K+ + π - : cτ = 3.91 fm Φ(1020) → K+ + K- : cτ = 46.5 fm Σ-(1385) → Λ + π - : cτ = 5.08 fm Λ(1520) → p + K- : cτ = 12.7 fm Should be sensitive to the late phase of the hadronic fireball Regeneration Rescattering of decay products ⇒ Provide information on the time span between chemical and kinetic freeze-out

  41. Recombination and Rescattering of Resonances Picture adapted from C. Markert and P. Fachini Hot and dense medium Particle yields K* K π π K K Particle spectra π K* Time

  42. Measurement of Resonances: Σ(1385) and Λ(1520) STAR: PRC71, 064902 (2005)

  43. Rescattering after Chemical Freeze-Out STAR: PRC71, 064902 (2005)

  44. Comparison to Chemical Equilibrium Expectation Pb+Pb, √sNN = 17.3 GeV Pb+Pb, √sNN = 17.3 GeV NA49: pub. in preparation HGM: F. Becattini et al.

  45. Scaling Properties of the Φ Meson No scaling with K+ × K- (coalescence picture) Scaling with (s-Quarks)2 Φ = ss K+ ∝ s-Quarks K- + Λ ∝ s-Quarks _ _

  46. K+/π + and Λ/π – Compared to Statistical Model A. Andronic et al., PLB676, 142 (2009)

  47. Energy Dependence of K/π Ratios Quite sharp maximum in K+/π+ ratio Indication for phase transition (?) PRC77, 024903 (2008)

  48. Antibaryon-Baryon Ratios S = -3 S = -2 S = -1 S = 0 NA49: PRC78, 034918 (2008)

  49. Baryon-Meson-Ratios

More Related