AI 中文总结
本研究借助AMPT模型的CAT模块，以两种方法探究7.7-200 GeV金-金碰撞的手征磁效应，发现11.5-27 GeV、20-50%中心度存在显著信号，且与STAR数据吻合，信号随能量变化显著。
AI 中文摘要
高能重离子碰撞有潜力产生手征不平衡夸克的局域区域，反映量子色动力学的拓扑特征。该现象可能在夸克胶子等离子体中诱导局域P宇称和CP宇称破坏。手征磁效应（CME）预测，在这类碰撞产生的强磁场中会发生电荷分离，通常通过电荷依赖的方位角关联（Δγ）进行研究。本研究使用配备手征反常输运（CAT）模块的多相输运（AMPT）模型，研究质心系能量√s_NN=7.7-200 GeV的金-金碰撞中的CME。采用两种独立方法：一是直接相减手征化学势μ5为零和有限时的关联量⟨N_partΔγ⟩，二是事件形状选择（ESS）方法。结果显示，在11.5-27 GeV能量范围和20-50%中心度范围内存在显著的CME信号，此时AMPT模型与STAR实验数据吻合良好；两种方法提取的CME分数在这些能量下的不确定度范围内一致。但在7.7 GeV和200 GeV时，CME信号均消失。这些发现表明，CME的可观测性关键取决于磁场的动态演化和部分子相的化学冻结时间，二者随碰撞能量显著变化。
英文摘要
High-energy heavy-ion collisions have the potential to create local domains of chirality-imbalanced quarks, reflecting the topological characteristics of quantum chromodynamics. This phenomenon can potentially induce local $\mathcal{P}$ and $\mathcal{CP}$ violations in the quark-gluon plasma. The Chiral Magnetic Effect (CME) predicts an electric charge separation along the intense magnetic field generated during these collisions, which is typically investigated through charge-dependent azimuthal correlations ($Δγ$). In this work, we investigate the CME in Au+Au collisions at $\sqrt{s_{NN}} = 7.7 - 200$ GeV using a multiphase transport (AMPT) model equipped with a Chiral Anomaly Transport (CAT) module. we employ two independent methods: direct subtraction of the correlator $\langle N_{part}Δγ\rangle$ between simulations with zero and finite chiral chemical potential $μ_5$, and the event-shape-selection (ESS) approach. Our results reveal a significant CME signal within the energy range of 11.5-27 GeV and the centrality range of $20-50\%$, where the AMPT model aligns well with STAR experimental data. Furthermore, the CME fractions extracted by both methods are consistent within uncertainties across these energies. However, the CME signal disappears at both 7.7 and 200 GeV. These findings underscore that the observability of the CME critically depends on both the dynamic evolution of the magnetic field and the chemical freeze-out time of the partonic phase, which vary significantly with collision energy.
