Elliptic flow of $\varphi$ and $\Omega$ via quark recombination mechanism in relativistic heavy-ion collisions

Abstract

Multi-strange hadrons, such as the $\varphi$ meson and $\Omega$ baryon, serve as unique probes for the properties of the quark-gluon plasma in relativistic heavy-ion collisions. Using a quark recombination model with the quark phase-space information parameterized in a viscous blastwave, we show that the elliptic flow $v_2$ of $\varphi$ and $\Omega$ can be describled by quark recombination in a wide energy range from $\sqrt{s_{NN}}$ = 7.7 GeV to 5.02 TeV. We check the scaling properties of $v_2$ of $\varphi$ and $\Omega$ and find the number-of-constituent-quark (NCQ) scaled $v_2$ of $\varphi$ and $\Omega$ are approximately equal. We further present the $v_2$ of strange quarks at hadronization extracted from $\varphi$ and $\Omega$ data. We find the $v_2$ of strange quarks is close to the NCQ-scaled $v_2$ of $\varphi$ and $\Omega$ at $\sqrt{s_{NN}}$ = 7.7-200 GeV, but significant larger than the latter at $\sqrt{s_{NN}}$ = 2.76-5.02 TeV, suggesting that the $v_2$ of strange quarks cannot be simply equated to the NCQ-scaled $v_2$ of $\varphi$ and $\Omega$. Our results demonstrate that the quark recombination mechanism is valid for $\varphi$ and $\Omega$ production in heavy-ion collisions at $\sqrt{s_{NN}}$ = 7.7 GeV to 5.02 TeV, indicating the existence of constituent quark degree of freedom at these energies.

arXiv comment8 pages, 6 figures, 3 tables. Comments are welcome