现实的Polyakov圈扩展Nambu-Jona-Lasinio模型中沿冻结线的温度波动
Temperature fluctuations in a realistic Polyakov-loop extended Nambu--Jona-Lasinio Model along the freeze-out line
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中文总结 AI 辅助
研究在现实PNJL模型中沿冻结线的温度波动，通过扩展和重参数化该模型，研究二阶温度累积量\(C_2\)行为，发现其在CEP和一阶相边界附近有凹陷结构，相关结果或为高阶事件平均横向动量波动实验测量提供理论基础。
中文摘要 AI 辅助
我们扩展并重新参数化了Polyakov-Nambu-Jona-Lasinio（PNJL）模型，以再现零重子化学势下的晶格模拟数据，并将其临界端点（CEP）定位在BES-II实验能量范围内。使用这个现实的PNJL模型，我们研究了沿冻结线的二阶温度累积量\(C_2\)的行为，旨在理解STAR合作组观察到的两粒子横向动量关联\(C_{p_T}\)的非单调能量依赖性。我们的结果在相图上的CEP和一阶相边界附近的\(C_2\)中显示出明显的凹陷结构。沿着实验提取的冻结线，凹陷最小值出现在7.7 GeV左右，其趋势与STAR观察到的一致，表明\(C_{p_T}\)的非单调依赖性可能与CEP有关。我们的结果还表明，诸如\(C_3/C_2^2\)或\(C_4/C_2^3\)的累积量比消除了初始体积波动的影响，可能更好地揭示潜在的临界波动。可以通过纳入临界动力学的流体动力学或输运模拟进行进一步验证。这些结果和预测可能为未来高阶事件平均横向动量波动的实验测量提供先验理论基础。
英文摘要
We extend and reparameterize the Polyakov--Nambu--Jona-Lasinio (PNJL) model to reproduce lattice simulation data at zero baryon chemical potential and to position its critical endpoint (CEP) within the BES-II experimental energy range. Using this realistic PNJL model, we investigate the behavior of the second-order temperature cumulant $C_2$ along the freeze-out line, aiming to understand the non-monotonic energy dependence of the two-particle transverse momentum correlation $C_{p_T}$ observed by the STAR Collaboration. Our results show a distinct dip structure in $C_2$ near the CEP and the first-order phase boundary on the phase diagram. Along the experimentally extracted freeze-out line, the dip minimum occurs around 7.7 GeV, and its trend is consistent with that observed by STAR, suggesting that the non-monotonic dependence of $C_{p_T}$ may be related to the CEP. Our results also indicate that cumulant ratios such as $C_3/C_2^2$ or $C_4/C_2^3$ eliminate the influence of initial volume fluctuations and may better reveal the underlying critical fluctuations. Further verification could be pursued through hydrodynamic or transport simulations that incorporate critical dynamics. These results and predictions might provide an a priori theoretical basis for future experimental measurements of higher-order event-mean transverse momentum fluctuations.
