1. Behind QGP Investigating the matter of the early Universe Investigating the matter of the early Universe Is the form of this matter Quark Gluon Plasma? Is the form of this matter Quark Gluon Plasma? What energy density, temperature? What energy density, temperature? Evidence for a Quark Fluid instead of a QGP Evidence for a Quark Fluid instead of a QGP Further properties of the matter Further properties of the matter Exploring the properties of the QCD Matter Máté Csanád, Eötvös University Budapest ISSP’06, August 29 – September 7, Erice

2. M. Csanád, ISSP’06 Erice 2 Discovering new laws of Nature "In general we look for a new law by the following process. First we guess it. Then we compare the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is — if it disagrees with experiment it is wrong.” /R.P. Feynman/

3. M. Csanád, ISSP’06 Erice 3 How did the Universe look like? Expectation: Quark Gluon Plasma Expectation: Quark Gluon Plasma Form of matter? Form of matter? Plasma? Gas? Fluid? Plasma? Gas? Fluid? Degrees of freedom? Degrees of freedom? Quarks and gluons? Quarks and gluons? Energy, temperature? Energy, temperature? Lattice QCD: Lattice QCD: deconfined above ~ 170MeV  2 terakelvin We will see: rather Quark Fluid than QGP We will see: rather Quark Fluid than QGP Metaphor or frozen world Metaphor or frozen world Theoretically predicted other forms of ice Theoretically predicted other forms of ice Experiment: smash ice to ice, detect re-frozen ice-particles Experiment: smash ice to ice, detect re-frozen ice-particles A lot predictions or guesses based on QGP failed A lot predictions or guesses based on QGP failed

4. M. Csanád, ISSP’06 Erice 4 M. Csanád, T. Csörgő, A. Ster et al. nucl-th/0512078 Elliptic flow: v 2 Second Fourier coefficient of Second Fourier coefficient of p t -spectra in transverse plane angle Gas, no interaction: spherical symmetry, v 2 = 0 Gas, no interaction: spherical symmetry, v 2 = 0 Hydrodynamic, collective behavior: v 2 > 0 Hydrodynamic, collective behavior: v 2 > 0 Fluid dynamics describes v 2 Fluid dynamics describes v 2

5. M. Csanád, ISSP’06 Erice 5 Relativistic Perfect Fluids Success of hydro models Success of hydro models Elliptic flow Elliptic flow Hydro scaling of spectra slopes and correlation length’ Hydro scaling of spectra slopes and correlation length’ A new family of exact solutions: A new family of exact solutions: T. Csörgő, M. I. Nagy, M. Csanád: nucl-th/0605070 T. Csörgő, M. I. Nagy, M. Csanád: nucl-th/0605070 Two improvement to the Bjorken solution: Two improvement to the Bjorken solution: Finite Rapidity distribution ~ Landau’s solution Finite Rapidity distribution ~ Landau’s solution Relativistic acceleration Relativistic acceleration Velocity field Number density Temperature

6. M. Csanád, ISSP’06 Erice 6 Advanced  0 estimate Width of dn/d  distribution is due to acceleration, controlled by parameter Width of dn/d  distribution is due to acceleration, controlled by parameter Acceleration yields longitudinal explosion Acceleration yields longitudinal explosion Bjorken estimate underestimates initial energy density Bjorken estimate underestimates initial energy density Here  f /  0  15 usually

7. M. Csanád, ISSP’06 Erice 7 Advanced  0 estimate Fits to BRAHMS dn/d  data:  2 Fits to BRAHMS dn/d  data:  2 Correction factors of  0 /  Bj  2.0 – 2.2 Correction factors of  0 /  Bj  2.0 – 2.2 Inital energy density of  0 ~ 10 – 30 GeV/fm 3 Inital energy density of  0 ~ 10 – 30 GeV/fm 3

8. M. Csanád, ISSP’06 Erice 8 Temperature estimate Buda-Lund hydro model compared to the data (fits) Buda-Lund hydro model compared to the data (fits) At freeze-out, 1/8 of the volume above deconfinement temperature At freeze-out, 1/8 of the volume above deconfinement temperature At this high temperature: not gas, but fluid! At this high temperature: not gas, but fluid! spectra v2v2 Csanád, Csörgő, Ster, nucl-th/0310040, nucl-th/0311102, nucl-th/0403074 spectra v2v2

9. M. Csanád, ISSP’06 Erice 9 Universal hydro scaling of v 2 Buda-Lund hydro : prediction of scale function I 1 /I 0 (2003,2004) Buda-Lund hydro : prediction of scale function I 1 /I 0 (2003,2004) PHENIX (2005), PHOBOS (2006) and STAR (2005) data do collapse PHENIX (2005), PHOBOS (2006) and STAR (2005) data do collapse Prediction based on perfect hydro is VALID Prediction based on perfect hydro is VALID Csörgő, Akkelin, Hama, Lukács, Sinyukov (Phys. Rev. C67, 034904, 2003) Csanád, Csörgő, Lörstad, Ster (Nucl. Phys. A742:80-94,2004) Csanád, Csörgő, Lörstad, Ster et al. nucl-th/0512078 I 1 /I 0

10. M. Csanád, ISSP’06 Erice 10 Scaling and scaling violations Universal hydro scaling breaks Universal hydro scaling breaks VALENCE QUARK number scaling sets in VALENCE QUARK number scaling sets in Fluid of QUARKS!! Fluid of QUARKS!! PHENIX Collaboration, nucl-ex/0608033

11. M. Csanád, ISSP’06 Erice 11 Chiral symmetry restoration? Prediction:  ’ mass reduction in hot and dense matter due to U A (1) symmetry restoration Prediction:  ’ mass reduction in hot and dense matter due to U A (1) symmetry restoration Idea: measure (m t ) dependence at low momenta Idea: measure (m t ) dependence at low momenta Kapusta, Kharzeev, McLerran Phys.Rev.D53:5028-5033,1996 Z. Huang, X-N. Wang Phys.Rev.D53(1996)5034 Vance, Csörgő Kharzeev Phys.Rev.Lett.81:2205-2208,1998 NA44, S+Pb

12. M. Csanád, ISSP’06 Erice 12 Why the  (m t ) dependence Prediction: In hot and dense matter  ’ mass reduction  Enhanced  ’ content Decay:  ’  +  + +  -  (  0 +  + +  − )+  + +  − Long lifetime Average p t of  ’s 138 MeV  More non-interacting  ’s at 138 MeV (m t ) measures ratio of interacting  ’s (m t ) measures ratio of interacting  ’s A hole in (m t ) PHENIX FINAL DATA Au+Au 200 GeV S. S. Adler et al., PRL93,152302(2004) (m t ) measures fraction of interacting  ’s (m t ) measures fraction of interacting  ’s

13. M. Csanád, ISSP’06 Erice 13 Analysis of new, low p t data U A (1) restoration tested U A (1) restoration tested Results critically dependent on understanding of statistical and systematic errors Results critically dependent on understanding of statistical and systematic errors Additional analysis required for definitive statement Additional analysis required for definitive statement PHENIX PRELIMINARY M. Csanád for the PHENIX Collaboration, Quark Matter 2005, Budapest nucl-ex/0509042

14. M. Csanád, ISSP’06 Erice 14 What matter do we see? We see a perfect fluid We see a perfect fluid Elliptic flow: hydro signal Elliptic flow: hydro signal Broad range success of hydro models Broad range success of hydro models It is deconfined It is deconfined High enough temperatures based on lQCD High enough temperatures based on lQCD Degrees of freedom: quarks Degrees of freedom: quarks Valence quark number scaling complimentary to hydro scaling Valence quark number scaling complimentary to hydro scaling Signal of partial symmetry restoration Signal of partial symmetry restoration Mass reduction of  ’ (preliminary) Mass reduction of  ’ (preliminary) A lot more not covered here A lot more not covered here Rare probes, penetrating probes, jet suppression… Rare probes, penetrating probes, jet suppression…

15. M. Csanád, ISSP’06 Erice 15 Where do we go? Explore all properties of the Quark Matter Explore all properties of the Quark Matter Analyse more data Analyse more data Make further guesses Make further guesses Use higher luminosity Use higher luminosity Full map of the QCD phase diagram Full map of the QCD phase diagram Go to higher energy Go to higher energy Compare to lower energy data Compare to lower energy data Use different colliding systems (e, p) Use different colliding systems (e, p) Columbus has just arrived to the new world Columbus has just arrived to the new world