标题： 从$^{40,48}$Ca$+^{40,48}$Ca 实验数据中得到的同位旋扩散，在费米能量下：与输运模型计算的直接比较 显示英文标题

标题： Isospin diffusion from $^{40,48}$Ca$+^{40,48}$Ca experimental data at Fermi energies: Direct comparisons with transport model calculations

摘要： 本文通过将实验数据与过滤传输模型计算进行比较，研究了在35 MeV/核子下交叉轰击$^{40,48}$Ca$+^{40,48}$Ca 反应中的同位旋平衡。通过中心性变化研究同位旋输运比的演化来研究同位旋扩散。使用准靶核（QP）残留物的不对称参数$\delta=(N-Z)/A$作为同位旋敏感观测量，同时使用一种最新的碰撞参数重建方法进行中心性排序。提出了一种全局可观测量的基准，以评估耦合GEMINI++的反对称分子动力学（AMD）模型在耗散碰撞研究中的相关性。我们的结果表明，为了再现用于同位旋输运和中心性研究的可观测量，考虑团簇形成的重要性。在AMD模型中，我们证明了碰撞参数重建方法的适用性，使得能够直接与实验数据进行比较，以研究同位旋扩散。对于两者，我们观察到随着碰撞参数从9 fm减少到3 fm，存在同位旋平衡的趋势，但未达到完全平衡。还观察到对模型中使用的状态方程刚度的弱敏感性，对于富中子反应，实验趋势的再现效果更好。 显示英文摘要

摘要： This article presents an investigation of isospin equilibration in cross-bombarding $^{40,48}$Ca$+^{40,48}$Ca reactions at 35 MeV/nucleon, by comparing experimental data with filtered transport model calculations. Isospin diffusion is studied using the evolution of the isospin transport ratio with centrality. The asymmetry parameter $\delta=(N-Z)/A$ of the quasiprojectile (QP) residue is used as isospin-sensitive observable, while a recent method for impact parameter reconstruction is used for centrality sorting. A benchmark of global observables is proposed to assess the relevance of the antisymmetrized molecular dynamics (AMD) model, coupled to GEMINI++, in the study of dissipative collisions. Our results demonstrate the importance of considering cluster formation to reproduce observables used for isospin transport and centrality studies. Within the AMD model, we prove the applicability of the impact parameter reconstruction method, enabling a direct comparison to the experimental data for the investigation of isospin diffusion. For both, we evidence a tendency to isospin equilibration with an impact parameter decreasing from 9 to 3 fm, while the full equilibration is not reached. A weak sensitivity to the stiffness of the equation of state employed in the model is also observed, with a better reproduction of the experimental trend for the neutron-rich reactions.