Quark number scaling of $p_T$ spectra for $\hat{I}\text{c◯}$ and $\ddot{I}•$ in relativistic heavy-ion collisions

Abstract

We show that the experimental data of transverse momentum ($p_T$) spectra of $\hat{I}\text{c◯}$ baryon and $\ddot{I}•$ meson at mid-rapidity in heavy-ion collisions exhibit the constituent quark number scaling in a wide energy range from RHIC to LHC. Such a scaling behavior is a direct consequence of quark combination mechanism via equal velocity combination and provides a very convenient way to extract the $p_T$ spectrum of strange quarks at hadronization. We present the results of strange quarks obtained from the available data and study the properties in particular the energy dependence of the averaged transverse momentum $⟨p_T⟩$ and the transverse radial flow velocity $⟨{\hat{I}}^2⟩$ with a hydrodynamics-motivated blast-wave model.

7 pages, 5 figures