"Table 170" of "Anisotropic flow and flow fluctuations of identified hadrons in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV"

The first measurements of elliptic flow of $\mathrm{\pi}^{\pm}$, $\mathrm{K}^{\pm}$, $\mathrm{p}+\bar{\mathrm{p}}$, $\mathrm{K_{S}^{0}}$, $\Lambda+\bar{\Lambda}$, $\mathrm{\phi}$, $\mathrm{\Xi^{\mp}}$, and $\mathrm{\Omega^{\mp}}$ using multiparticle cumulants in Pb--Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV are presented. Results obtained with two- ($v_2\{2\}$) and four-particle cumulants ($v_2\{4\}$) are shown as a function of transverse momentum, $p_{\rm T}$, for various collision centrality intervals. Combining the data for both $v_2\{2\}$ and $v_2\{4\}$ also allows us to report the first measurements of the mean elliptic flow, elliptic flow fluctuations, and relative elliptic flow fluctuations for various hadron species. These observables probe the event-by-event eccentricity fluctuations in the initial state and the contributions from the dynamic evolution of the expanding quark--gluon plasma. The characteristic features observed in previous $p_{\rm T}$-differential anisotropic flow measurements for identified hadrons with two-particle correlations, namely the mass ordering at low $p_{\rm T}$ and the approximate scaling with the number of constituent quarks at intermediate $p_{\rm T}$, are similarly present in the four-particle correlations and the combinations of $v_2\{2\}$ and $v_2\{4\}$. In addition, a particle species dependence of flow fluctuations is observed that could indicate a significant contribution from final state hadronic interactions. The comparison between experimental measurements and CoLBT model calculations, which combine the various physics processes of hydrodynamics, quark coalescence, and jet fragmentation, illustrates their importance over a wide $p_{\rm T}$ range.

本文首次报道了在√s_NN = 5.02 TeV的铅-铅（Pb--Pb）核碰撞中，利用多粒子累积量（multiparticle cumulants）对π±、K±、p+$ar{p}$、Kₛ⁰、Λ+$ar{Λ}$、φ、Ξ∓以及Ω∓的椭圆流（elliptic flow）开展的测量结果。采用双粒子累积量（two-particle cumulants）与四粒子累积量（four-particle cumulants）获取的v₂{2}与v₂{4}结果，以横动量（transverse momentum, $p_{
m T}$）为函数，展示了不同碰撞中心度区间下的分布。结合v₂{2}与v₂{4}的实验数据，我们还首次报道了不同强子种类的平均椭圆流（mean elliptic flow）、椭圆流涨落（elliptic flow fluctuations）以及相对椭圆流涨落（relative elliptic flow fluctuations）的测量结果。这些观测量可用于探究初始态（initial state）的逐事件偏心率涨落（event-by-event eccentricity fluctuations），以及膨胀夸克胶子等离子体（quark-gluon plasma）的动力学演化贡献。此前通过双粒子关联（two-particle correlations）对已鉴别强子开展横动量微分各向异性流测量时观测到的特征，即低$p_{
m T}$区的质量序关系与中间$p_{
m T}$区随组分夸克数目呈现的近似标度行为，在四粒子关联（four-particle correlations）以及v₂{2}与v₂{4}的组合结果中同样存在。此外，本研究观测到流涨落存在粒子种类依赖性，这暗示末态强子相互作用可能存在显著贡献。将实验测量结果与结合流体力学（hydrodynamics）、夸克聚结（quark coalescence）以及喷注碎裂（jet fragmentation）等多种物理过程的CoLBT模型计算结果进行对比，可见该模型在宽横动量范围内的重要性。