标题： 相对论重离子碰撞中将各向异性测量与流体力学联系起来的非流体动力学问题 显示英文标题

标题： The nonflow issue in connecting anisotropy measurements to hydrodynamics in relativistic heavy-ion collisions

摘要： 流体力学可以描述相对论重离子碰撞中大部分测量到的方位角各向异性。 许多各向异性测量值受到非流关联（即与全局事件相关的关联无关）的污染。 这些非流污染会导致从数据-流体力学比较中提取的物理结果出现错误或降低准确性，特别是在依赖测量中的细微差异时。 在STAR最近的预印本（arXiv:2401.06625）中提取铀核变形参数时，通过有限的STAR可接受范围内子事件评估了非流污染。 在这篇笔记中，我们证明这种评估是不充分的，并通过HIJING模型说明非流可能引起的效应有多大，在该模型中所有关联均为非流且非流体力学。 因此，我们得出结论认为提取的铀核变形参数尚不成熟，并强调了认真评估或修正非流污染的重要性，不仅针对此STAR分析，而且更普遍地适用于依赖于比较各向异性测量与流体力学计算的研究。 显示英文摘要

摘要： Hydrodynamics can describe majority of the measured azimuthal anisotropies in relativistic heavy-ion collisions. Many of the anisotropy measurements are contaminated by nonflow correlations (i.e., those unrelated to global event-wise correlations). Those nonflow contamination can cause incorrectness or compromise the accuracy of the physics extracted from data-hydrodynamics comparison, particularly when one relies on subtle difference in the measurements. In the recent preprint by STAR (arXiv:2401.06625) extracting the Uranium nucleus deformation parameter, nonflow contamination is assessed by subevents in the limited STAR acceptance. In this note, we demonstrate that such assessment is inadequate and illustrate how large an effect nonflow can cause by using the HIJING model, in which all correlations are nonflow and non-hydrodynamic. We thereby conclude that the extracted Uranium deformation parameter is premature and emphasize the importance of an earnest assessment of or correction for nonflow contamination, not only for this STAR analysis but more generally for studies relying on comparing anisotropy measurements to hydrodynamic calculations.