论文标题
在RHIC和LHC的相对论重离子碰撞的早期，重夸克的弹道扩散
Ballistic diffusion of heavy quarks in the early stage of relativistic heavy ion collisions at RHIC and LHC
论文作者
论文摘要
我们研究了RHIC和LHC高能核冲突的早期魅力夸克的扩散。本研究的主要新颖性是引入了在不断发展的Glasma（EV-Glasma）中传播的重夸克所带来的颜色电流，这是导致通过培养基极化而耗能损失的原因。我们计算在热力化阶段的符合符号的横向动量扩展，即$σ_p$，以及扩散对Nucleus-Nucleus碰撞中核修饰因子的影响。能量损失的净效应在热时间阶段是边缘的。这项研究是通过计算坐标扩展，$σ_x$以及与Langevin Dynamics进行比较完成的。 EV-Glasma中的$σ_p$超出了hydro制度结束时标准的langevin Dynamics的结果。我们将其解释为对作用在魅力夸克上的颜色力的记忆结果，这意味着$σ_p\ propto t^2 $。此外，$σ_x\ propto t^2 $在hydro阶段中表明，eV-Glasma中的魅力夸克在弹道扩散状态下。
We study the diffusion of charm quarks in the early stage of high energy nuclear collisions at the RHIC and the LHC. The main novelty of the present study is the introduction of the color current carried by the heavy quarks that propagate in the evolving Glasma (Ev-Glasma), that is responsible of the energy loss via polarization of the medium. We compute the transverse momentum broadening, $σ_p$, of charm in the pre-thermalization stage, and the impact of the diffusion on the nuclear modification factor in nucleus-nucleus collisions. The net effect of energy loss is marginal in the pre-thermalization stage. The study is completed by the calculation of coordinate spreading, $σ_x$, and by a comparison with Langevin dynamics. $σ_p$ in Ev-Glasma overshoots the result of standard Langevin dynamics at the end of the pre-hydro regime. We interpret this as a result of memory of the color force acting on the charm quarks that implies $σ_p\propto t^2$. Moreover, $σ_x\propto t^2 $ in the pre-hydro stage shows that the charm quark in the Ev-Glasma is in the regime of ballistic diffusion.
