论文标题
相对论重离子碰撞中超子自旋极化的流体动力研究
A hydrodynamic study of hyperon spin polarization in relativistic heavy ion collisions
论文作者
论文摘要
我们使用音乐流体动力学模型具有多相传输（AMPT）前平衡动力学，对重离子碰撞中的超子的自旋极化进行系统研究。我们的模型计算很好地描述了$λ$极化的测得的碰撞能量，中心性，速度和$ p_t $依赖性。我们还研究并预测$ξ^ - $和$ω^ - $的全局自旋极化，这是碰撞能量的函数，该函数为磁力矩，自旋和自旋极化的质量依赖性提供了基线。对于局部自旋极化，我们计算横向$λ$极化的径向和方位角成分，并找到可能反映圆形涡流结构的特定调节行为。但是，我们的模型未能描述纵向和横向$λ$极化的方位角依赖性，这表明在自由度自由度的热平衡的假设下，具有旋转Cooper-Frye公式的流体动力框架需要改善。
We perform a systematic study of the spin polarization of hyperons in heavy-ion collisions using the MUSIC hydrodynamic model with A Multi-Phase Transport (AMPT) pre-equilibrium dynamics. Our model calculations nicely describe the measured collision-energy, centrality, rapidity, and $p_T$ dependence of $Λ$ polarization. We also study and predict the global spin polarization of $Ξ^-$ and $Ω^-$ as a function of collision energy, which provides a baseline for the studies of the magnetic moment, spin, and mass dependence of the spin polarization. For the local spin polarization, we calculate the radial and azimuthal components of the transverse $Λ$ polarization and find specific modulating behavior which could reflect the circular vortical structure. However, our model fails to describe the azimuthal-angle dependence of the longitudinal and transverse $Λ$ polarization, which indicates that the hydrodynamic framework with the spin Cooper-Frye formula under the assumption of thermal equilibrium of spin degree of freedom needs to be improved.
