Heavy Ions Collisions (results and questions)

1. Heavy Ions Collisions (results and questions) Anatoly Litvinenko Elena Litvinenko litvin@moonhe.jinr.ru litvin@nf.jinr.ru 1

2. Outline. Ядерная материя при большой плотности энергии Новое фазовое состояние – легко верится Workshop on Heavy Ions, New York, Nov. 29 - Dec 1, 1974. The name ”Quark Gluon Plasma” was coined by Eduard Shuryak in1978. 2

3. The conception of the phase diagram of QCD as a function of time L. McLerran and N. Samios 3

4. Ideal massless gas Bosons -- 1- degree of freedom: Fermions -- 1- degree of freedom: 2 quarks 3 quarks 4

5. A few words about values Bosons -- 1- degree of freedom: Fermions -- 1- degree of freedom: 2 quarks 3 quarks 5

6. Lattice QCD Frithjof Karsch, arXiv:hep-lat/0106019v2 (2001) F. Karsch, Lecture Notes in Physics 583 (2002) 209. 6

7. space-time structure of heavy ions collisions kineticfreeze-out (no collisions) Chemical freeze-out (no particles production) Parton-parton interaction Initial inelastic collisions

8. Relativistic Heavy Ion Collider (RHIC) 8 8

9. 2 rings, 3.8 km circumference. Polarized p and Nucleus up to Au. Top energies (each beam): 100 GeV/nucleon Au-Au. 250 GeV polarized p-p. NIM, v.499, p. 235-880, (2003) 9 9

10. STAR

11. The PHENIX Detector Детектор PHENIX регистрирует различные частицы после столкновения: фотоны, электроны, мюоны и адроны (пионы и протоны).

12. The PHOBOS Detector PHOBOS Spectrometer Vertex 1m Octagon Paddle Trigger Counter Ring Counters Cerenkov Counter 137000 Silicon Pad Channels ZDC ZDC DX magnet DX Magnet 12m Be Beampipe

13. 95° h=0 30° 2.3° h=2 30° 15° The BRAHMS Experiment

14. LHC

15. Rapidity Lorens boost Pseudorapidity Transverse mass 15

16. questions have to be answered Can we achieve high energy density in nuclei-nuclei collisions ? What is the barion density of prodused hadronic matter? Is established thermodynamic equilibrium? Connected question Can we make conclusion about from experiment? 16

17. STAR EVENTS http://www.star.bnl.gov/ Central Au+Au(200 GeV) p+p(200 GeV) 17

18. Centrality classification • Number of participant • Value of impact parameter Geometrical cross section • In percent from the geometrical cross section Centrality 18

19. QUESTION I(a) How much energy lost the primary hadrons? What is barion density of prodused hadronic matter? Can we make some conclusion from experiment? 19

20. Stopping power Net protons distribution BRAHMS collaboration PRL 93, 1020301 (2004),

21. Stopping power (73 ± 6) GeV / nucleon (73 ± 6) % BRAHMS collaboration PRL 93, 1020301 (2004),

22. QUESTION I(b) Can we have high energy density in nuclei-nuclei collisions ? Can we make some conclusion from experiment? 22

23. Energy density and Bjorken equation J.D. Bjorken, Phys. Rev. D27 (1983) 140. 23

24. Dependence on centrality of charged hadron density S.S. Adleret al., Phys. Rev. C 71, 034908 (2005) 24

25. Dependence on pseudorapidity of charged hadron B. Alver et al. Phys. Rev. C 83, 024913 (2011)PHOBOS Coll. Do not confuseit is the other distribution

26. Dependence on pseudorapidity of charged hadron The CMS collaboration, J.High Energy Phys 08, p.141 (2011)

27. Dependence on pseudorapidity of charged hadron The CMS collaboration, J.High Energy Phys 08, p.141 (2011) «LHC multiplicity is two times greater than at RHIC»

28. Dependence on centralty of charged hadron S.S. Adleret al., Phys. Rev. C 71, 034908 (2005)

29. S.S. Adleret al., Phys. Rev. C 71, 034908 (2005)

30. Energy density and Bjorken equation Historically, the energy density is estimated using

31. Energy density and crossing time crossing time For and Energy density is determined from final state parameters 31

32. QUESTION I(b) Can we achieve high energy density in nuclei-nuclei collisions ? Can we make some conclusion from experiment? Yes! For RHIC and LHC energy 32

33. QUESTION II Is equilibrium state of hot and dense hadronic matter achieved? What is conclusions from experiment? 33

34. QUESTION II Is equilibrium state of hot and dense hadronic matter achieved? • The possible observable • Particle ratios • Particle spectra • Collective flows • … ? 34 34

35. Particle ratio and statistical models • One assumes that particles are produced by a thermalizedsystem with temperature T and baryon chemical potential • The number of particles of mass mper unit volume is : These models reproduce the ratios of particle yields withonly two (or three )parameters 35 35

36. Particle ratios and statistical model(s) Peter Braun-Munzinger, Krzysztof Redlich, Johanna Stachel arXiv:nucl-th/0304013v1, (2003) «Of particular interest is the extent towhich the measured particle yields are showing equilibration.» 36 36

37. A. Tawfik ; arXiv:hep-ph/0508244v3 22 Mar 2006 STAR Coll., Nucl. Phys. A 757 (2005) 102 • Statistical methods have become an important tool to study the properties • of the fireball created in high energy heavy ion collisions, where they • succeed admirably in reproducing measured yield ratios. • Can this success betaken as evidence that the matter produced in these collisions has reached thermal and chemical equilibrium? • Can the temperature and chemical potential values extracted from such statistical model fits be interpreted as theequilibrium properties of the collision matter?

38. Particle ratios S. S. Adler, et al., Phys. Rev. C69 (2004) 034909 38 38

39. Particle ratios and statistical models chemical freez-out Nucl. Phys. A758, No.1-2, p.184, (2005) 39 39

40. Particle ratios and statistical models 40 40

41. Particle ratios and statistical models 41 41

42. Peter Braun-Munzinger, Krzysztof Redlichb, Johanna Stachel arXiv:nucl-th/0304013 v1 3 Apr 2003 42

43. Low energy (NA49) Katarzyna Grebieszkowfor the NA49 and the NA61 Collaborations ACTA PHYSICA POLONICA Vol. B41, No 2,p.427 (2010)

44. Particle (hadrons) spectra kinetic freeze-out 44 44

45. Particle (hadrons) spectra R. Stock; «Quark Matter 99 Summary: Hadronic Signals» arXiv:hep-ph/9911408v1 19 Nov 1999 45 45

46. T. Csorgo and B. Lorstad, Phys. Rev. C 54, 1390 (1996) BorisTomasic, arXiv:nucl-th/0304079 v1 25 Apr 2003 blast-wave model Pions, nucleons and also kaons decouple all quite suddenly from the whole transverse profile of the fireball. For all of them the freeze-out happens at the same proper time, measured in a frame that co-moves longitudinally with the fluid element of the expanding firebal The radial density distribution at the freeze-out is uniform. Longitudinal expansion is boost-invariant. In this study, the transverse expansion is parametrized through rapidity, which depends linearly on the radial coordinate. 46

47. BorisTomasic, arXiv:nucl-th/0304079 v1 25 Apr 2003 47

48. Particle (hadrons) spectra A Iordanova (for the STAR Collaboration);J. Phys. G35, p.044008, (2008 48 48

49. elliptic flow Elliptic flow Directed flow Space eccentricity Coordinate space asymmetry  momentum space anisotropy 49 49

50. Elliptic flow • For big value of elliptic flow you need save space anisotropy for a long enough time • The value of elliptic flow is sensitive to the Equation of State (EoS) Importance of elliptic flow • Give information about equilibration time • Give information about EoS On the next slides shown how ensemble of free streaming particles lost space eccentricity 50 50