1. A.Litvinenko VBLHEP JINR Определение центральности столкновения ядер с использованием калориметра cпектаторов в эксперименте MPD@NICA A.Litvinenko, litvin@moonhe.jinr.ru M.Golubeva, F.Guber, A.Ivashkin, A.Kurepin, INR, Moscow A.Litvinenko, E.Litvinenko, A.Isupov, I.Migulina, V.Peresedov, JINR, Dubna

2. A.Litvinenko VBLHEP JINR  Introduction Some definitions Spectators UrQMD generator  UrQMD generator LAQGSM generator  LAQGSM generator  UrQMD - SHIELD - LAQGSM  Conclusions Outline

3. A.Litvinenko VBLHEP JINR NICA

4. A.Litvinenko VBLHEP JINR MPD

5. A.Litvinenko VBLHEP JINR  Quasi-Classical picture  b – not observable  observables b Nuclear-Nuclear collisions

6. 6 Centrality classification  Value of impact parameter Geometrical cross section  In percent from the geometrical cross section Centrality Corresponds to the region impact parameter

7. Centrality classification 1. 2. Fraction from total cross-section 3. Number of participant …. ? Impact parameter

8. 8 Centrality classification

9. A.Litvinenko VBLHEP JINR The importance of the centrality classification elliptic flow scaling with space eccentricity short equlibration time Space eccentricity Elliptic flow Nuclear Physics A V757, No. 1-2, p.184,2005

10. A.Litvinenko VBLHEP JINR The importance of the centrality study Jet Quenching – nuclear modification factor vs centrality Nuclear Physics A V757, No. 1-2, p.184,2005 Nuclear modification factor

11. A.Litvinenko VBLHEP JINR The importance of the centrality study

12. A.Litvinenko VBLHEP JINR

13. Nucleon spectators (spectrum) Yu.Bayukov et al., YaF V.35, No. 4, p.960, (1982) R.Ammarи et al., Pisma v JETF, V.94, No. 4, p.189, (1989)

14. A.Litvinenko VBLHEP JINR Spectator spectrum

15. A.Litvinenko VBLHEP JINR

16. Front view of ZDC. The squares size is 5 x 5 cm x cm

17. A.Litvinenko VBLHEP JINR ZDC@MPD geometrical efficiency central hole out of ZDC

18. A.Litvinenko VBLHEP JINR Simulation Transport – Geant3 and Geant4, generates UrQMD and LAQGSM framework MpdRoot

19. A.Litvinenko VBLHEP JINR URQMD generator, Sqrt(S)=5 GeV Total kinetic energy of all nucleons directed to ZDC Optimistic results with UrQMD

20. A.Litvinenko VBLHEP JINR UrQMD generator, Sqrt(S)=9 GeV Total kinetic energy of all nucleons directed to ZDC Optimistic results with UrQMD

21. A.Litvinenko VBLHEP JINR The accuracy of impact parameter determination for MC with UrQMD

22. 22 The centrality resolution evaluations √S=9 AGeV

23. A.Litvinenko VBLHEP JINR But The NA49 collaboration. Eur. Phys. J., A2, 383, (1998)

24. A.Litvinenko VBLHEP JINR LAQGSM high-energy event generator But

25. A.Litvinenko VBLHEP JINR LAQGSM generator, Sqrt(S)=5 GeV Total kinetic energy of all nucleons and fragments directed to ZDC Taking into account spectator fragments

26. A.Litvinenko VBLHEP JINR LAQGSM generator, Sqrt(S)=9 GeV Total kinetic energy of all nucleons and fragments directed to ZDC Taking into account spectator fragments

27. A.Litvinenko VBLHEP JINR SHIELD event generator

28. A.Litvinenko VBLHEP JINR LAQGSM, Sqrt(S)=5 GeV Total kinetic energy of all nucleons and fragments directed to ZDC URQMD, Sqrt(S)=5 GeV

29. A.Litvinenko VBLHEP JINR

30. At large impact parameters the most of spectator nucleons are bound in fragments. The NA49 collaboration. Eur. Phys. J., A2, 383, (1998) Experimental data : the deposited energy for different types of spectators in dependence of the centrality

31. A.Litvinenko VBLHEP JINR All nucleons directed to the hole of ZDC (rectangle 10x10cm 2 ) 0 % - 60 %60 % - 80 % 80 % - 100 %

32. A.Litvinenko VBLHEP JINR At large impact parameters the most of spectator nucleons are bound in fragments. The NA49 collaboration. Eur. Phys. J., A2, 383, (1998) Experimental data : the deposited energy for different types of spectators in dependence of the centrality

33. 33 The centrality resolution evaluations √S=9 AGeV Kinetic energy of all spectators directed to solid angle 5 º

34. The centrality resolution evaluations √S=9 AGeV

37. A.Litvinenko VBLHEP JINR The centrality determination: ZDC (energy) + number of charged barrel tracks

38. A.Litvinenko VBLHEP JINR UrQMD - SHIELD - LAQGSM b < 3 фм (0 – 4 %)

39. A.Litvinenko VBLHEP JINR UrQMD - SHIELD - LAQGSM 3 фм < b < 9.5 фм (4 – 40 %)

40. A.Litvinenko VBLHEP JINR UrQMD - SHIELD - LAQGSM 9.5 фм < b (40 – 100 %)

41. A.Litvinenko VBLHEP JINR Centrality determination in some experiment y=0 y=3 y>6 STAR PHENIX NA49 ZDC Only STARTPC only PHENIXBBC & ZDC

42. A.Litvinenko VBLHEP JINR Conclusions The SHIELD and LAQGSM could be used for NICA/MPD simulations under mpdroot. The SHIELD and LAQGSM angular distributions of the spectators differ from URQMD picture. The experimental study of the spectator distributions and calorimeter resolution have to be performed on the extracted beam of NUCLOTRON-M at the fixed target.

43. A.Litvinenko VBLHEP JINR Conclusions Работа выполнена при поддержке грантов РФФИ 10-02-01036-а 11-02-01026-а

44. A.Litvinenko VBLHEP JINR Backup slides

45. A.Litvinenko VBLHEP JINR

46. Fast evaluations: the movement of spectators at NICA/MPD The conclusion: Magnetic field of MPD will not change the polar angles for spectators at ZDC position it will only slightly changes the azimutal angles

47. A.Litvinenko VBLHEP JINR

50. Centrality classification C.E.Aguilar et al., Brazilian Journal of Physics, V.34,No.1,p.319,(2004)

51. A.Litvinenko VBLHEP JINR Calorimeter No.1

52. A.Litvinenko VBLHEP JINR Calorimeter No.1

53. A.Litvinenko VBLHEP JINR Calorimeter No.1

54. A.Litvinenko VBLHEP JINR Calorimeter No.1

55. A.Litvinenko VBLHEP JINR Linearity Resolution Longitudinal distribution

56. A.Litvinenko VBLHEP JINR Calorimeter No.1

57. A.Litvinenko VBLHEP JINR CONCLUSION

58. A.Litvinenko VBLHEP JINR Пространственное разрешение

59. A.Litvinenko VBLHEP JINR ZDC

60. A.Litvinenko VBLHEP JINR ZDC + Multiplicity 1000 Min Bias

61. A.Litvinenko VBLHEP JINR ZDC + Multiplicity 1000 Min Bias

62. A.Litvinenko VBLHEP JINR

63. PHENIX ZDC + BBC

64. A.Litvinenko VBLHEP JINR NA49 VCAL (ZDC)

65. 65 TIME = 0 fm/c,

66. 66 TIME = 1 fm/c,

67. 67 TIME = 2 fm/c,

68. 68 TIME = 3 fm/c,