Bayesian Inference of the Specific Shear and Bulk Viscosities of the Quark-Gluon Plasma at Crossover from $\varphi$ and $\Omega$ Observables

Abstract

Due to their weak final state interactions, the $\varphi$ meson and $\Omega$ baryon provide unique probes of the properties of the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. Using the quark recombination model with the quark phase-space information parameterized in a viscous blastwave, we study the transverse-momentum spectra and elliptic flows of $\varphi$ and $\Omega$ in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV. The viscous blastwave includes non-equilibrium deformations of thermal distributions due to shear and bulk stresses and thus carries information on the specific shear viscosity $\eta /s$ and the specific bulk viscosity $\zeta /s$ of the QGP. We perform a model-to-data comparison with Bayesian inference and simultaneously obtain $\eta /s=(2.08_{-1.09}^{+1.10})/4\pi$ and $\zeta /s=0.06_{-0.04}^{+0.04}$ at $90\%$ C.L. for the baryon-free QGP at crossover temperature of about $160$ MeV. Our work provides a novel approach to simultaneously determine the $\eta /s$ and $\zeta /s$ of the QGP at hadronization.

Comments: 7 pages, 3 figures, 1 table. Presentation improved and discussions added. Accepted version to appear in PRC