Ahmad, N.

Chattopadhyay, S.

Irfan, M.

Jahan, H.

Senger, P.

GSI Repository

Production of hyperons at FAIR energiesH. Jahan∗1, S. Chattopadhyay2, P. Senger3, N. Ahmad1, and M. Irfan11AMU, Aligarh, India; 2VECC, Kolkata, India; 3GSI, Darmstadt, GermanyOne of the main aims of studying relativistic heavy-ioncollisions is to investigate the characteristics of nuclearmatter under extreme conditions of temperature and en-ergy density. Under high temperature and/or baryon den-sity, nuclear matter is expected to undergo a transition toa state of free quarks and gluons, known as quark-gluonplasma (QGP)[1]. The determination of yields of strangeparticles is one of the key parameters to study the prop-erties of the matter created in high energy heavy-ion col-lisions. The relative enhancement of strange and multi-strange baryons as well as their ratios in central heavy ioncollisions in comparison to those for proton induced inter-actions have also been suggested as a possible signature forthe formation of QGP [2]. In the present work, A Multi-Phase Transport (AMPT) model [3] is employed to studyproduction of strange particles in cental Au+Au collisionsat FAIR energies (i.e. ELab = 5 to 40 AGeV). In orderto see whether the hyperon production is sensitive to thedegrees-of-freedom in the collision volume, both the stringmelting (partonic matter) and the default mode (hadronicmatter) of the AMPT model have been used for calculatingthe particle yields.The results of the calculations are shown as excitationfunctions of Λ0 and Λ¯0 hyperons, Ξ− and Ξ¯+ hyperons,and Ω− and Ω¯+ hyperons in the upper, center, and lowerpanel of Fig. 1, respectively. The yields have been calcu-lated in the FAIR energy range for both modes of AMPT,i.e., string melting (partonic) and default (hadronic). In thecase of Λ¯0 hyperons, the yield for hadronic production isone order of magnitude higher than the yield for partonicproduction at top SIS100 energies (11 A GeV), an effectwhich is clearly measurable. A similar effect, althoughsmaller in magnitude, is found for Ξ¯+ hyperons. In con-trast, the yields of Ξ− and Ω− hyperons for partonic pro-duction are well above the yield for hadronic productionin the beam SIS100 energy range. The yield of Ω¯+ hy-perons seems not to be sensitive to the production mecha-nism. However, this result should be checked by a calcula-tion with much better statistics. In conclusion, according tothe AMPD code the yields of hyperons and anti-hyperonsproduced in central Au+Au collisions at FAIR energies ex-hibit a measurable sensitivity to the degrees-of-freedom inthe fireball.References[1] S. A. Bass, M. Gyulassy, H. Sto¨cker and W. Greiner, J. Phys.G 25, R1 (1999) [arXiv:hep-ph/9810281]∗ hushnud.jahan@gmail.com[2] J. Rafelski and B. Mu¨ller, Phys. Rev. Lett. 48, 1066(1982); J.Rafelski, Phys. Rep. 88, 331 (1982);P. Koch, B. Mu¨ller andJ. Rafelski, Phys. Rep. 142,167 (1986)[3] B. Zhang C. M. Ko, B. A. Li and Z. W.Lin, Phys. Rev. C 61,067901 (2000); Z. W. Lin,S. Pal, C. M. Ko, B. A. Li, and B.Zhang, Phys.Rev. C [arXiv:nucl-th/0011059]LabE5 10 15 20 25 30 35 40 Yield-410-310-210-110110 AMPT(parton)0Λ AMPT(hadron)0Λ AMPT(parton)0Λ AMPT(hadron)0ΛLabE5 10 15 20 25 30 35 40 Yield-310-210-1101 AMPT(parton)-Ξ AMPT(hadron)-Ξ AMPT(parton)+Ξ AMPT(hadron)+ΞLabE5 10 15 20 25 30 35 40 Yield-410-310-210 AMPT(parton)-Ω AMPT(hadron)-Ω AMPT(parton)-Ω AMPT(hadron)-ΩFigure 1: Yield of hyperons in central Au+Au collisions asfunction of beam energy calculated with the AMPT codewith string melting (partonic) and without (hadronic). Up-per panel: Λ0 and Λ¯0 hyperons. Center panel: Ξ− and Ξ¯+hyperons. Lower panel: Ω− and Ω¯+ hyperons.NQM-CBM-40 GSI SCIENTIFIC REPORT 201356 doi:10.15120/GR-2014-1-NQM-CBM-40

Production of hyperons at FAIR energies

http://repository.gsi.de/record/67786/files/NQM-CBM-40.pdf

Production of hyperons at FAIR energies

Abstract

Similar works

Full text

Available Versions

GSI Repository