UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2007 Meeting


Section: Nuclear and Elementary Particles Physics


Title:
On the study of the experimental information in relative time scale of Hubble


Authors:
Alexandru Jipa, Calin Besliu, Amelia Horbuniev


Affiliation:
Atomic and Nuclear Physics Chair, Faculty of Physics, University of Bucharest, Romania


E-mail
ameliahorbuniev2000@yahoo.com


Keywords:
highly and dense nuclear matter, relative Hubble time scale


Abstract:
Introduction Considering the similarities between the Universe evolution scenarios after the “Big-Bang” and the behavior of highly excited matter formed during the Relativistic Nuclear Collisions (RNC) soon after collision [1-4], was estimated to be a parameter (microscopic Hubble constant – nuclear) for the expansion rate of RNC, similar to the “Hubble cosmological constant”[5-7]. Study of some interesting physics quantities in the Hubble time scale The properties of some hadrons that are forming during the evolution of nucleus-nucleus collisions gave us the information of temperature, densities, fireball sizes or evolution velocity of the emitting source [8, 9]. Considering these similarities between the evolutions for both universes have been calculated for highly and dense nuclear matter [10]: 1. tcosmo – the cosmological time that makes direct connection between the two phenomena through a relation between time and nuclear temperature [11]. 2. H - the expansion rate of the nuclear collision – similar with Hubble parameter of, or Hv/d – ratio between the expansion velocity and the size of the participant region or Hρ– from the Einstein –de Sitter scenario which is directly connected with the nuclear matter density. The good according where obtained with results from the Buda –Lund models - HBuda-Lund based on the nuclear hydrodynamics flow with a tri-dimensional hyperboloid evolution [13-15] of particle source, has considering a relative Hubble time scale. Experimental results and interpretations It has been taken in consideration the nuclear collisions from two energies at 4.5AGeV/c (Collaboration University of Bucharest – JINR Dubna Russia) were obtained temperatures of 93- 140 MeV [8], densities around 4 •ρ0 (Collaboration University of Bucharest – JINR Dubna Russia) and macroscopic time of 35- 140 µs, and at 200 A GeV energy(Collaboration University of Bucharest – BRAHMS-BNL) with T=300 MeV, 10•ρ0 , 4- 12 µs. A relative Hubble time scale has been defined. It was studied the experimental distributions in different ranges of rapidity (the participant hot range and the range of spectator), as well as at different flow angles. Energies and angels were influenced the evolution. These dependences show a very fast evolution through the decrease of the values inside a range to a zone of constant values (plateau-like behaviors), as suggested by other models. The relative Hubble time scale is simple and elegant method to study the evolution of the interesting physics quantities experimentally obtained. Bibliography [1].David K. Scott- Prog.Part.Nucl.Phys. IV(1981)5 [2].B.B.Back et.al. (PHOBOS Collaboration) - Nucl.Phys.A. 757 (2005) 28-101 [3].J.Adams et.al. (STAR Collaboration) - Nucl.Phys. a. 757 (2005) 102-183 [4].K.Adcox (PHENIX Collaboration) - Nucl.Phys. a. 757 (2005) 184-283 [5].Steven Weinberg – The first three minutes of the Universe – Politics Publishing Company, Bucharest, 1981 (Romanian translation) [6]. Jacqes Merlau-Ponty – Cosmologie du XXe sicle – Editions Gallimard, 1965 [7].Stephen W. Hawking – A brief history of trime. From the Bing-Bang to Black Holes – Humanitas Publishing Company, Bucharest, 2005 (Romanian translation) [8].Al.Jipa-On the temperature of the pionic Sources in Nucleus-Nucleus Collisions at 4,5 A GeV/c, J.Phys. G: Nucl.Part. Phys. 22, (1996) 231-242 [9].I.G.Bearden et.al. (NA 44 Collaboration), Phys. Rev. Lett. 78 (1997) 2080 [10].Al.Jipa, C.Beşliu, I. S. Zgură, O.Ristea, C.Ristea, A. Horbuniev, I. Arsene, D. Argintaru, M. Călin, T. Eşeanu, V. Covlea, B. Iliescu – On a „microscopic constant” from relativistic nuclear collisions – Int. Journal of Modern Phys. E: (2007) [11].K.A.Olive and S. Rudaz – Comment about Astrophysics Reviews – Written dec 1985 [12]. O. Gron- A new standard model of the universe –Eur. J. Phys. 23 (2002) 135-144 [13].M.Csanád, T. Csörgö, B. Lörswtad-Buda Lund hydro model for ellipsoidally symmetric fireballs and the elliptic flow at RHIC- arXiv:nulcl-th/0310040v1-13.oct.2003 [14].H. Reeves – Big-Bang nucleosynthesis and the quark-hadron phase transipion-Phys. Rep. 2001, nr. 6, (1991) 335-354 [15].H. Reeves- Nucl. Phys.A 488 (1988) 665c