AI 中文总结
该研究基于fRG方法结合流体动力学，计算9个碰撞能量下净质子数涨落及其比值，发现含临界涨落的C₄/C₂对碰撞能呈非单调依赖，为高能重离子碰撞的临界现象研究提供了理论参考。
AI 中文摘要
基于泛函重整化群（fRG）方法得到的涨落，我们在9个碰撞能量（√s_NN=7.7-200 GeV）下的粒子化流体动力学冻结超曲面上计算净质子数涨落及其比值C₂/C₁、C₃/C₂和C₄/C₂，其中包含从临界终点（CEP）产生的常规涨落和临界涨落。计算中采用与实验测量相同的横动量和快度接受窗口，实现质子数涨落的同位旋随机化以及整体重子守恒效应，并将结果与无临界涨落的基线结果对比。研究发现，对于低阶累积量如C₂/C₁，临界与非临界结果差异较小，但在低碰撞能区，差异随累积量阶数增加而增大；含临界涨落的C₄/C₂呈现对碰撞能的非单调依赖，而无临界涨落的结果中不存在该现象。
英文摘要
We compute the net-proton number fluctuations and their ratios $C_2/C_1$, $C_3/C_2$ and $C_4/C_2$ on the hydrodynamic freeze-out hypersurface of particlization at nine collision energies, $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV, based on the fluctuations obtained from the functional renormalization group (fRG) approach, where both the regular and the critical fluctuations arising from the critical end point (CEP) are included. The transverse momentum and rapidity acceptance windows as same as the experimental measurements, the isospin randomization for the proton number fluctuations, and the global baryon conservation effect are implemented in the calculations. The results are also compared with the baseline results without critical fluctuations. It is found that for the low-order cumulants, e.g., $C_2/C_1$ the difference between the critical and non-critical results is small, while the difference increases with the increasing order of cumulants in the region of low collision energy. A non-monotonic dependence on the collision energy is observed in $C_4/C_2$ with critical fluctuations, which is absent in the results without critical fluctuations.
Comments7+2 pages, 4 figures
