Strangeness Enhancement at the Hadronic Chemical Freeze-Out

  • V. V. Sagun Bogolyubov Institute for Theoretical Physics, Nat. Acad. of Sci. of Ukraine
  • D. R. Oliinychenko Bogolyubov Institute for Theoretical Physics, Nat. Acad. of Sci. of Ukraine, FIAS,Goethe-University
  • K. A. Bugaev Bogolyubov Institute for Theoretical Physics, Nat. Acad. of Sci. of Ukraine
  • J. Cleymans Department of Physics, University of Cape Town
  • A. I. Ivanytskyi Bogolyubov Institute for Theoretical Physics, Nat. Acad. of Sci. of Ukraine
  • I. N. Mishustin FIAS,Goethe-University, Kurchatov Institute, Russian Research Center
  • E. G. Nikonov Laboratory for Information Technologies, JINR
Keywords: chemical freeze-out, ys factor, Strangeness Horn, hadron multiplicities

Abstract

The chemical freeze-out of hadrons created in the high energy nuclear collisions is studied within a realistic version of the hadron resonance gas model. The chemical non-equilibrium of strange particles is accounted via the usual ys factor, which gives us an opportunity to perform a high quality fit with x2/dof ≃ 63.5/55 ≃ 1.15 of the hadronic multiplicity ratios measured from the low AGS to the highest RHIC energies. In contrast to the previous findings, we observe the strangeness enhancement at low energies instead of a suppression. In addition, the performed ys fit allows us to achieve the highest quality of the Strangeness Horn description with x2/dof = 3.3/14. For the first time, the top point of the Strangeness Horn is perfectly reproduced, which makes our theoretical horn as sharp as an experimental one. However, the ys fit approach does not sizably improve the description of the multistrange baryons and antibaryons. Therefore, an apparent deviation of the multistrange baryons and antibaryons from the chemical equilibrium requires a further explanation.

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Published
2018-10-28
How to Cite
Sagun, V., Oliinychenko, D., Bugaev, K., Cleymans, J., Ivanytskyi, A., Mishustin, I., & Nikonov, E. (2018). Strangeness Enhancement at the Hadronic Chemical Freeze-Out. Ukrainian Journal of Physics, 59(11), 1043. https://doi.org/10.15407/ujpe59.11.1043
Section
Fields and elementary particles