论文标题
各向异性流的有效剪切和散装粘度
Effective shear and bulk viscosities for anisotropic flow
论文作者
论文摘要
我们评估了重型离子碰撞中各向异性流动的粘性阻尼，以进行任意温度依赖的剪切和块状粘度。我们表明，阻尼仅由有效的剪切和散装粘度确定，这些粘度在温度下是加权平均值。我们确定$ \ sqrt {s _ {\ rm nn}} = 5.02 $ tev和200 GEV的核核碰撞的相关权重，通过运行理想和粘性水动力学模拟，对应于最大LHC和RHIC能量。有效的剪切粘度是由RHIC低于$ 210 $ MEV的温度驱动的，LHC的$ 280 $ MEV驱动，最大的贡献来自最低温度，刚好高于冻结。有效的大量粘度是由较高的温度驱动的，对应于碰撞的早期阶段。我们表明，在固定碰撞能量下，有效的粘度独立于中心性和系统大小，与外向辐射的平均横向动量相同。粘性阻尼的变化取决于雷诺数缩放。
We evaluate the viscous damping of anisotropic flow in heavy-ion collisions for arbitrary temperature-dependent shear and bulk viscosities. We show that the damping is solely determined by effective shear and bulk viscosities, which are weighted averages over the temperature. We determine the relevant weights for nucleus-nucleus collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV and 200 GeV, corresponding to the maximum LHC and RHIC energies, by running ideal and viscous hydrodynamic simulations. The effective shear viscosity is driven by temperatures below $210$ MeV at RHIC, and below $280$ MeV at the LHC, with the largest contributions coming from the lowest temperatures, just above freeze-out. The effective bulk viscosity is driven by somewhat higher temperatures, corresponding to earlier stages of the collision. We show that at a fixed collision energy, the effective viscosity is independent of centrality and system size, to the same extent as the mean transverse momentum of outgoing hadrons. The variation of viscous damping is determined by Reynolds number scaling.
