全息QCD临界点对夸克味道敏感
The holographic QCD critical point is sensitive to quark flavors
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中文总结 AI 辅助
本研究用依赖夸克味道的全息V-QCD模型研究致密QCD相结构，发现相图对拟合过程和物理环境敏感，β平衡物质存在临界端点，但重离子条件下相变消失，可能解释RHIC净质子涨落未现非单调信号。
中文摘要 AI 辅助
我们通过将依赖味道的全息V-QCD模型应用于两种不同的物理环境，研究了致密QCD物质的相结构：电荷中性、β平衡物质，以及具有固定电荷-重子数比n_Q/n_B = 0.4、与重离子碰撞相关的奇异中性物质。模型的夸克部分包含了两个无质量轻夸克和一个大质量奇异夸克的现实质量层级。我们发现，所得相图对用于将模型调谐至格点QCD热力学的过程以及物理环境的选择都高度敏感。使用我们偏好的拟合过程，我们发现β平衡物质表现出一个一阶相变，其终止于临界端点，该端点的密度显著低于早期全息研究中的结果。然而，在重离子条件下，该相变完全消失。这种显著的环境依赖性可能有助于解释为什么RHIC束流能量扫描II期最近的净质子累积量测量尚未揭示清晰的非单调涨落信号。我们沿着化学冻结曲线计算了高阶重子数累积量比率，以定量比较模型预测与实验数据。最后，我们还展示了通过将V-QCD与Thermal-FIST软件包中实现的重子共振气体模型匹配而获得的全局相图，并论证这种比较进一步支持了仅从V-QCD模型得出的结论。
英文摘要
We study the phase structure of dense QCD matter by applying the flavor-dependent holographic V-QCD model to two distinct physical environments: charge-neutral, beta-equilibrated matter, and strangeness-neutral matter with a fixed charge-to-baryon number ratio, n_Q/n_B = 0.4, relevant for heavy-ion collisions. The quark sector of the model incorporates the realistic mass hierarchy of two massless light quarks and a massive strange quark. We find that the resulting phase diagram depends sensitively on both the procedure used to tune the model against lattice QCD thermodynamics and the choice of physical environment. Using our preferred fitting procedure, we find that beta-equilibrated matter exhibits a first-order phase transition terminating at a critical endpoint located at significantly lower densities than in earlier holographic studies. However, this phase transition disappears entirely under heavy-ion conditions. This pronounced environmental dependence may help explain why recent net-proton cumulant measurements from Phase II of the RHIC Beam Energy Scan have not yet revealed clear non-monotonic fluctuation signatures. We calculate higher-order baryon number cumulant ratios along the chemical freeze-out curve to quantitatively compare the model predictions with experimental data. Finally, we also present global phase diagrams obtained by matching V-QCD to Hadron Resonance Gas models implemented in the Thermal-FIST package, and argue that this comparison further supports the conclusions drawn from the V-QCD model alone.
发表机构
- University of Helsinki（赫尔辛基大学）
- Chinese Academy of Sciences（中国科学院）
- University of Heidelberg（海德堡大学）
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