Extracting strange quark freeze-out information in Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV from $\phi$ and $\Omega$ production

TL;DR

This study uses a covariant quark coalescence model with a blast-wave parametrization to analyze strange quark freeze-out in Pb+Pb collisions at 2.76 TeV, fitting spectra and flow data of $$ and $$ particles.

Contribution

It demonstrates that the covariant quark coalescence model effectively describes $$ and $$ production and reveals complexities in interpreting elliptic flow scaling.

Findings

NCQ scaling holds for $v_2$ but scaled $v_2$ is smaller than strange quark $v_2$

The model accurately reproduces spectra and elliptic flows of $$ and $$

NCQ-scaled $v_2$ cannot be directly equated to strange quark $v_2$ at hadronization.

Abstract

Using a covariant quark coalescence model combined with a blast-wave-like analytical parametrization for (anti-)strange quark phase-space freeze-out configuration, we extract information on strange quark freeze-out dynamics in Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV by fitting the measured transverse momentum spectra and elliptic flows ($v_2$) of $\phi$ mesons and $\Omega$ baryons. We find that although both the measured and calculated $v_2$ of $\phi$ and $\Omega$ satisfy the number-of-constituent-quark (NCQ) scaling, the NCQ-scaled $v_2$ is significantly smaller than the $v_2$ of strange quarks, implying that the NCQ-scaled $v_2$ of $\phi$ and $\Omega$ cannot be simply identified as the $v_2$ of strange quarks at hadronization. Meanwhile, our results indicate that the covariant quark coalescence model can nicely describe the spectra and elliptic flows of $\phi$ and $\Omega$ simultaneously, suggesting the coalescence mechanism is still valid for $\phi$ and $\Omega$ production in Pb+Pb collisions at LHC energies.