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Review of Structures in the Energy Dependence of Hadronic Observables

Christoph Blume. Review of Structures in the Energy Dependence of Hadronic Observables. Int. Workshop on Critical Point and Onset of Deconfinement Florence, July 3-6, 2006. Critical point. 1st order. Cross over. Introduction Exploring the QCD Phase Diagram. Chemical freeze-out

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Review of Structures in the Energy Dependence of Hadronic Observables

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  1. Christoph Blume Review of Structures in the EnergyDependence of Hadronic Observables Int. Workshop on Critical Point and Onset of Deconfinement Florence, July 3-6, 2006

  2. Critical point 1st order Cross over IntroductionExploring the QCD Phase Diagram Chemical freeze-out points approach phase boundary at SPS energies Transition to QGP likely to happen in this region Ebeam = 20 - 158 AGeV (sNN = 6.3 - 17.3 GeV) Lattice calculations: Fodor and Katz Bielefeld-Swansea group Hadron gas fits (): J. Manninen et al. Christoph Blume Florence, July 3-6 2006

  3. IntroductionEnergy Dependence Any evidence for a phase transition (or the even critical point) in hadronic observables seen ? Look for “non-smooth” behaviour in the energy dependencies Prominent examples: “horn”, “kink”, “step” Any other structures? How significant are they? Comparison to hadronic models Transport models (UrQMD + HSD) Statistical models Identify “trivial” structures Baseline comparison Christoph Blume Florence, July 3-6 2006

  4. IntroductionHadronic Scenery at SPS Transition from baryon dominated to meson dominated system Statistical model: Transition at sNN  8 GeV Maximum of strangeness prod. Evidences for structures beyond this? J. Cleymans, H. Oeschler, K. Redlich, and S. Wheaton, hep-ph/0510283 Christoph Blume Florence, July 3-6 2006

  5. K++ /Nw Introduction”Horn” / “Kink” / “Step” STEP HORN KINK Christoph Blume Florence, July 3-6 2006

  6. SPS AGS RHIC IntroductionExperiments Christoph Blume Florence, July 3-6 2006

  7. IntroductionObservables Particle yields Pions Strangeness Transverse mass spectra Radial flow  EOS Elliptic flow Initial pressure Bose-Einstein correlations System size and lifetime Not discussed here: Fluctuations Christoph Blume Florence, July 3-6 2006

  8. / K+/+ -/ Full chem. equilibrium baseline K-/- / -++/ Particle YieldsEnergy Dependence of Particle Ratios UrQMD + HSD E.L. Bratkovskaya et al., PRC 69 (2004), 054907 Statistical hadron gas: P. Braun-Munzinger, J. Cleymans, H. Oeschler, and K. Redlich Nucl. Phys. A697 (2002) 902 s = 1 Christoph Blume Florence, July 3-6 2006

  9. Kaons and  deviate from stat. model for sNN  7-8GeV ? ? Different situation for hyperons Particle YieldsComparison to Statistical Model Statistical hadron gas: P. Braun-Munzinger, J. Cleymans, H. Oeschler, and K. Redlich Nucl. Phys. A697 (2002) 902 (data – model)/(data) (data – model)/(data) s = 1 Christoph Blume Florence, July 3-6 2006

  10. Particle YieldsPosition of Maxima Statistical model prediction: J. Cleymans, H. Oeschler, K. Redlich, and S. Wheaton, hep-ph/0510283 Christoph Blume Florence, July 3-6 2006

  11. Indications for sudden changes in kaon e.-dependence (?) Particle YieldsLocal Slope of Energy Dependence:  and K No significant structure for pions Christoph Blume Florence, July 3-6 2006

  12. s-quark carriers: K-, K0(1)  (incl. 0) 0,-, - (2) ±(3) s-quark carriers: K+, K0(1)  (incl. 0) 0,+, + (2) ±(3) (1) K0  K+, K0  K- by isospin symmetry (2) Taken from hadron gas fit by Becattini et al., if not measured. (3) Empirical factor ( + ) /  = 1.6 assumed.  1.5 (+ + -) Sudden change of strangeness production at sNN = 7-8GeV ? Particle YieldsComparison s- and s-Carriers Data: E802, E866, E895, E917, NA49  1.5 (+ + -) Christoph Blume Florence, July 3-6 2006

  13. Particle YieldsLocal Slope of Energy Dep.: s/s-Quarks Local slope seems to change quite fast for strangeness at sNN = 7-8GeV Smoother dependence for pions Christoph Blume Florence, July 3-6 2006

  14. Maximum in strangeness/pion ratio Same for s and s quarks Particle Yields(Anti-)Strangeness to Pion Ratio Difficult to model in hadronic scenarios Solid line: Statistical hadron gas model with s = 1 K. Redlich, priv. comm. Predicted as signal for the onset of deconfinement Dotted line: M. Gazdzicki and M.I. Gorenstein, Acta Phys. Polon. B30 (1999), 2705 Christoph Blume Florence, July 3-6 2006

  15. Transverse Mass SpectraEnergy Dependence of mt-m0  negatively charged Energy dependence of transverse activity seems to change around sNN = 7-8GeV General feature for pion, kaons and protons Quite robust observation Christoph Blume Florence, July 3-6 2006

  16. Transverse Mass SpectraLocal Slope of Energy Dependence: mt-m0 Significant change of local slope for pions and kaons around sNN = 7 GeV Similar for protons Christoph Blume Florence, July 3-6 2006

  17. Elliptic FlowEnergy Dependence ofv2 for Pions Mid-rapidity data, pt integrated Initial spatial anisotropy  different pressure gradients  momentum anisotropy v2 Energy dependence changes in SPS region Christoph Blume Florence, July 3-6 2006

  18. Elliptic FlowModel Comparison ofv2 for Pions Energy dependence of v2 not described by UrQMD Squeeze-out at lower energies not described w/o nuclear potential At higher energies: lack of inital pressure! Indication for onset of partonic flow at SPS? H. Petersen, Hot Quarks06 Christoph Blume Florence, July 3-6 2006

  19. Elliptic Flowv2 for Protons at 40A GeV Disappearance of proton flow? Evidence for 1st order phase transition H. Stöcker, nucl-th/0406018 ? Standard method different to cumulant method at mid-rapidity Larger systematic error Systematic study with higher precision needed Challenge for future experiments! NA49 PRC 68 (2003) 034903 Christoph Blume Florence, July 3-6 2006

  20. Bose-Einstein CorrelationsEnergy Dependence of Radius Parameters Christoph Blume Florence, July 3-6 2006

  21. Bose-Einstein CorrelationsEnergy Dependence of Radius Parameters No indication for strong energy dependence between AGS and RHIC Structures? But: Unresolved discrepancies between SPS experiments! kt 0.2GeV/c Christoph Blume Florence, July 3-6 2006

  22. Bose-Einstein CorrelationsModel Comparison: UrQMD NA49 data 20A – 158A GeV Reasonable description by transport model (R2out-R2side)1/2 slightly larger in model M. Bleicher, GRC06 QingFeng Li, Frankfurt Christoph Blume Florence, July 3-6 2006

  23. Bose-Einstein CorrelationsModel Comparison: UrQMD No structure in energy dependence in data and transport model  Data M. Bleicher, GRC06 QingFeng Li, Frankfurt Christoph Blume Florence, July 3-6 2006

  24. Summary Evidences for structures in hadronic exciation functions Around sNN = 7-8GeV Particle Yields Qualitatively close to to statistical model expectations Clear deviations seen for kaons and  Maxima in X/ ratios as in stat. model ? Indication for sudden change in strangeness e.-dep. Transverse mass spectra Sudden change of mt Change of radial flow  EOS ? Elliptic flow No clear evidence, higher presision data needed Bose-Einstein correlations No evidence for structure High precision data mandatory! Christoph Blume Florence, July 3-6 2006

  25. Thanks! Christoph Blume Florence, July 3-6 2006

  26. RpA ? SPS High ptEnergy Dependence of RCP for Pions and h- Strongest drop of RCP between s = 17.3GeV and s = 62.4GeV Any onset at low energies? Christoph Blume Florence, July 3-6 2006

  27. Particle YieldsEnergy Dependence of K+/+ Central Pb+Pb/Au+Au Mid-rapidity ratios Same structure as for 4 Christoph Blume Florence, July 3-6 2006

  28. Particle YieldsEnergy Dependence of 4 Yields AGS NA49 BRAHMS Central Au+Au, Pb+Pb Access to the energy dependence of identified particle yields in the range sNN = 2.5 – 200 GeV Christoph Blume Florence, July 3-6 2006

  29. Transverse Mass SpectraInverse Slope Parameters of Kaons Y. Hama et al. Braz. J. Phys. 34 (2004), 322, hep-ph/0309192 Feature cannot be described by transport models Hydro calculation with assumption of 1st order phase transition  Change of EOS seen? Christoph Blume Florence, July 3-6 2006

  30. Transverse Mass SpectraInverse Slope Parameters of Kaons Step in energy dependence Seems to be absent in p+p p+p compilation from: M. Kliemant, B. Lungwitz, and M. Gazdzicki, PRC 69 (2004) 044903 Christoph Blume Florence, July 3-6 2006

  31. Transverse Mass Spectra“Hydro” - Model • Basic model: • Common freeze-out of all particle types • Boost invariant longitudinal expansion • Transverse expansion is modelled by a velocity profile • “Standard” version: Schnedermann, Sollfrank, and Heinz, Phys. Rev. C46 • Extended version: • Resonance contribution included • Baryonic resonances introduce dependence on B • Chemical freeze-out: Tch and B taken from freeze-out curve • Thermal freeze-out: System cools down, therefore assume: • Conservation of entropy • Conservation of effective particle numbers U. Wiedemann and U. Heinz, Phys. Rev. C56 (1997) 3265 B. Tomasik, nucl-th/0304079 Christoph Blume Florence, July 3-6 2006

  32. Transverse Mass Spectra“Hydro” – Model Fits p - K- Convave  Resonances Exponential Shoulder  Radial flow E895: nucl-ex/0306033 NA49: Phys. Rev. C66 (2002) 054902, nucl-ex/0403023 PHENIX: Phys. Rev. C69 (2004) 024904, nucl-ex/0307022 Christoph Blume Florence, July 3-6 2006

  33. Transverse Mass SpectraEnergy Dependence of Fit Parameter Fit to -, K- and p Tch Box-shaped source profile and linear velocity profile Fit range 0.1 < mt-m0 < 0.8 GeV Energy dependence of Tf seems to change around 30 AGeV Thermal and chemical freeze-out different? Single freeze-out model? Continous increase of T Christoph Blume Florence, July 3-6 2006

  34. Fit parameters: Transverse Mass SpectraBlast Wave Fits Blast wave implementation: F. Retiere and M. Lisa nucl-th/0312024 Good description of all particle species at SPS energies Christoph Blume Florence, July 3-6 2006

  35. Bose-Einstein CorrelationsBlast Wave Model Fits Combined fit to HBT radii and transverse mass spectra Emission function: Fit parameters: Good fit to the data slight deviations in Rside at high kt Blast wave implementationn: M. Lisa, F. Retiere, nucl-th/0312024 Christoph Blume Florence, July 3-6 2006

  36. Bose-Einstein CorrelationsThermal Freeze-Out Parameters Tchem J. Cleymans, K. Redlich, Phys. Rev. C60, 054908 (1999) Slightly increasing temperature with beam energy Approx. constant transverse geometrical Radii (Rbox 2Rgauss) Finite emission duration at SPS energies Christoph Blume Florence, July 3-6 2006

  37. Possible explanation: Constant mean free path freeze-out condition Transition baryon  meson dominated Bose-Einstein CorrelationsEnergy Dependence of Freeze-Out Volume Minimum in freeze-out volume in SPS region But: Unresolved inconsistencies between SPS experiments! D. Adamová et al. (CERES collaboration), Phys. Rev. Lett. 90 (2003) 022301. Christoph Blume Florence, July 3-6 2006

  38. Bose-Einstein CorrelationsEnergy Dependence of Freeze-Out Volume kt 0.15GeV/c Christoph Blume Florence, July 3-6 2006

  39. Particle YieldsAntilambda-Antiproton Ratio Increase above 1 towards lower energies consistent with recent NA49 data Models predict ratio < 1 Hadron Gas 1: J. Manninen et al. Hadron Gas 2: K. Redlich et al. Hadron Gas 3: J. Rafelski et al. Christoph Blume Florence, July 3-6 2006

  40. Strong increase of B/B ratio in SPS energy range Particle YieldsAntibaryon-Baryon Ratio Energy dependence weakens with increasing strangeness content NA49 preliminary No indications for structures in energy dependence Lines: Statistical hadron gas model J. Manninen et al. Fit to 4 data! Christoph Blume Florence, July 3-6 2006

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