Beam energy scan using a viscous hydro+cascade model

Abstract

Following the experimental program at BNL RHIC, we perform a similar "energy scan" using 3+1D viscous hydrodynamics coupled to the UrQMD hadron cascade, and study the collision energy dependence of pion and kaon rapidity distributions and $m_T$-spectra, as well as charged hadron elliptic flow. To this aim the equation of state for finite baryon density from a Chiral model coupled to the Polyakov loop is employed for hydrodynamic stage. 3D initial conditions from UrQMD are used to study gradual deviation from boost-invariant scaling flow. We find that the inclusion of shear viscosity in the hydrodynamic stage of evolution consistently improves the description of the data for Pb-Pb collisions at CERN SPS, as well as of the elliptic flow measurements for Au-Au collisions in the Beam Energy Scan (BES) program at BNL RHIC. The suggested value of shear viscosity is $\eta /s\ge 0.2$ for $\sqrt{s_{NN}}=6.3\dots 39$ GeV.

4 pages, to appear in the proceedings of Strangeness in Quark Matter 2013 conference

References in corpus (5)

• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• Particlization in hybrid models
• Inclusive charged hadron elliptic flow in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV
• An effective chiral Hadron-Quark Equation of State
• Uniform description of bulk observables in the hydrokinetic model of A+A collisions at RHIC and LHC

Cited by in corpus (4)

• A 3+1 dimensional viscous hydrodynamic code for relativistic heavy ion collisions
• Estimation of the shear viscosity at finite net-baryon density from A+A collision data at $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV
• Anisotropic flow in transport+hydrodynamics hybrid approaches
• Observables in ultrarelativistic heavy-ion collisions from two different transport approaches for the same initial conditions