Phenomenology of strangeness production at high energies

Abstract

The strange-quark occupation factor (${\gamma }_s$) is determined from the statistical fit of the multiplicity ratio ${\mathrm{K}}^{+}/{\pi }^{+}$ in a wide range of nucleon-nucleon center-of-mass energies ($\sqrt{s_{NN}}$). From this single-strange-quark-subsystem, ${\gamma }_s(\sqrt{s_{NN}})$ was parametrized as a damped trigonometric functionality and successfully implemented to the hadron resonance gas model, at chemical semi-equilibrium. Various particle ratios including ${\mathrm{K}}^{-}/{\pi }^{-}$, $\mathrm{\Lambda }/{\pi }^{-}$, and $\bar{\mathrm{\Lambda }}/{\pi }^{-}$ are well reproduced. The phenomenology of ${\gamma }_s(\sqrt{s_{NN}})$ suggests that, the hadrons (${\gamma }_s$ raises) at $\sqrt{s_{NN}}\simeq 7$GeV seems to undergo a phase transition to a mixed phase (${\gamma }_s$ declines), which is then derived into partons (${\gamma }_s$ remains unchanged with increasing $\sqrt{s_{NN}}$), at $\sqrt{s_{NN}}\simeq 20$GeV.

Comments: 6 pages, 2 figures, accepted for publication in EPL