The iS3D particlization module simulates the emission of hadrons from heavy-ion collisions via Monte-Carlo sampling of the Cooper-Frye formula which converts fluid dynamical information into local phase-space distributions for hadrons. The code package includes multiple choices for the non-equilibrium correction to these distribution functions: the 14-moment approximation, first-order Chapman-Enskog expansion, and two types of modified equilibrium distributions. This makes it possible to explore to what extent heavy-ion experimental data are sensitive to different choices for $\delta f_n$, presently the main source of theoretical uncertainty in the particlization stage. We validate our particle sampler with a high degree of precision by generating several million hadron emission events from a longitudinally boost-invariant hypersurface and comparing the event-averaged particle spectra and space-time distributions to the Cooper-Frye formula.

中文翻译：

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重离子碰撞流体动力学模拟中的粒子化：iS3D 模块

iS3D 粒子化模块通过 Cooper-Frye 公式的蒙特卡罗采样模拟重离子碰撞中强子的发射，该公式将流体动力学信息转换为强子的局部相空间分布。代码包包括对这些分布函数的非平衡校正的多种选择：14 矩近似、一阶 Chapman-Enskog 展开和两种类型的修正平衡分布。这使得探索重离子实验数据对 $\delta f_n$ 的不同选择敏感到什么程度成为可能，这是目前粒子化阶段理论不确定性的主要来源。