Phenomenology of light- and strange-quark simultaneous production at high energies

Abstract

This letter presents an extension of EPL116(2017)62001 to light- and strange-quark nonequilibrium chemical phase-space occupancy factors (${\gamma }_{q,s}$). The resulting damped trigonometric functionalities relating ${\gamma }_{q,s}$ to the nucleon-nucleon center-of-mass energies $(\sqrt{s_{NN}})$ looks very similar except different coefficients. The phenomenology of the resulting ${\gamma }_{q,s}(\sqrt{s_{NN}})$ describes a rapid decrease at $\sqrt{s_{NN}}\lesssim 7$GeV followed by a faster increase up to $\sim 20$GeV. Then, both ${\gamma }_{q,s}$ become nonsensitive to $\sqrt{s_{NN}}$. Although these differ from ${\gamma }_s(\sqrt{s_{NN}})$ obtained at ${\gamma }_q(\sqrt{s_{NN}})=1$, various particle ratios including ${\mathrm{K}}^{+}/{\pi }^{+}$, ${\mathrm{K}}^{-}/{\pi }^{-}$, $\mathrm{\Lambda }/{\pi }^{-}$, $\bar{\mathrm{\Lambda }}/{\pi }^{-}$, ${\mathrm{\Xi }}^{+}/{\pi }^{+}$, and $\mathrm{\Omega }/{\pi }^{-}$, can well be reproduced, as well. We conclude that ${\gamma }_{q,s}(\sqrt{s_{NN}})$ should be instead determined from fits of various particle yields and ratios but not merely from fits to the particle ratio ${\mathrm{K}}^{+}/{\pi }^{+}$.

Comments: 10 pages, 3 figures, accepted for publication in PEPAN letters