论文标题
全球$λ$在重型离子碰撞中的两极分化2.4--7.7 GEV：梅森场相互作用的效果
Global $Λ$ polarization in heavy-ion collisions at energies 2.4--7.7 GeV: Effect of Meson-Field Interaction
论文作者
论文摘要
基于三流体模型，在2.4 $ \ leq \ sqrt {s_ {nn}} \ leq $ 7.7 GEV中，全局$λ$极化在2.4 $ \ leq \ sqrt {s_ {s_ {s_ {s_ {nn}} \ sqrt {s_ {s_ {nn}} \ leq $ 7.7 GEV。考虑了热涡度和介子术语（由Csernai，Kapusta和Welle提出的）贡献到全球极化。将结果与来自最近和正在进行的HADES实验的数据进行了比较。可以预测，如果测量值是同样的接受，则在$ \ sqrt {s_ {nn}} \ $ 3 GEV处达到极化。极化的值对上述贡献的相互作用非常敏感。特别是，热涡度导致极化从中间速度到前向/向后的速度的大幅度增加，而介子场的贡献显着平移了速度依赖性。事实证明，极化对状态方程的细节非常敏感。虽然碰撞动力学随着碰撞能量的降低而变得较少，但目前的极化方法基于热平衡的假设。发现在冻结阶段达到平衡，但是这种平衡需要更长的相对论能量。
Based on the three-fluid model, the global $Λ$ polarization in Au+Au collisions at 2.4 $\leq\sqrt{s_{NN}}\leq$ 7.7 GeV is calculated, including its rapidity and centrality dependence. Contributions from the thermal vorticity and meson-field term (proposed by Csernai, Kapusta and Welle) to the global polarization are considered. The results are compared with data from recent and ongoing STAR and HADES experiments. It is predicted that the polarization maximum is reached at $\sqrt{s_{NN}}\approx$ 3 GeV, if the measurements are performed with the same acceptance. The value of the polarization is very sensitive to interplay of the aforementioned contributions. In particular, the thermal vorticity results in quite strong increase of the polarization from the midrapidity to forward/backward rapidities, while the meson-field contribution considerably flattens the rapidity dependence. The polarization turns out to be very sensitive to details of the equation of state. While collision dynamics become less equilibrium with decreasing collision energy, the present approach to polarization is based on the assumption of thermal equilibrium. It is found that equilibrium is achieved at the freeze-out stage, but this equilibration takes longer at moderately relativistic energies.
