(3+1)-D viscous hydrodynamics at finite net baryon density: Identified particle spectra, anisotropic flows, and flow fluctuations across energies relevant to the beam-energy scan at RHIC

摘要

To study the bulk properties of quark-gluon plasma produced at beam-energy scan (BES) energies at the Relativistic Heavy Ion Collider (RHIC), we extend the (3 + 1)-dimensional viscous hydrodynamics CLVISC to include net baryon number conservation and Israel-Stewart-like equations for baryon diffusion with the NEOS-BQS equation of state, fluctuating initial conditions from the Monte Carlo Glauber model and the afterburner SMASH. This integrated framework is shown to provide a good description of identified particle spectra, mean transverse momenta, and anisotropic flows for different centralities and over a wide range of collision energies (7.7-62.4 GeV). It is found that the mean momenta of identified particles and anisotropic flows increase mildly with the collision energy due to larger radial flow. We further compute the multiple-particle cumulant ratio v(2){4}/v(2){2} of elliptic flow across BES energies, and find that the relative fluctuations of elliptic flow are insensitive to the collision energy, consistent with the preliminary STAR data. Our model provides a benchmark for understanding the RHIC-BES data and studying the critical properties and phase structure of hot and dense QCD matter.

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