Investigation of Chirality, Vorticity and Spin Polarization in Heavy ion Collisions

核物质是我们宇宙中所有可见物质的核心。虽然已知它是由夸克和胶子构成的，但核物质的结构和性质究竟是如何从夸克和胶子中产生的，仍然是基础物理学中的一个大问题。探索这个问题的一个重要方法是通过在相对论重离子对撞机（RHIC）和大型强子对撞机（LHC）上进行的核碰撞实验，这些实验产生了一种叫做夸克-胶子等离子体（QGP）的热“亚原子汤”。这个项目通过研究QGP在极强磁场和涡度场下的行为来帮助理解QGP。PI通过在这些场下发展QGP自旋输运的理论描述，执行现象学模拟来计算观测值，并分析与实验数据比较的含义来实现这一目标。除了从这些研究中提取QGP属性（这是当今核科学的主要前沿之一）之外，该项目还提供了参与和指导研究生和本科生进行研究以及开展各种公共宣传活动的机会。该项目的目的是研究在重离子碰撞中产生的大块物质的宏观手性、涡度和磁场与微观粒子自旋之间的相互作用所产生的新型输运。第一部分是定量地了解所谓的手性磁效应和相关的背景相关性。这是通过利用异常粘性流体动力学模拟框架来完成的，重点分析了初始核结构输入的影响。目标是实现对最新高精度等压线碰撞测量的解释，以及对从等压线到金-金碰撞的信号/背景演变的连贯解释。第二部分旨在推进具有角动量的流体动力学框架，并使用流体动力学和输运模型的组合在大范围的光束能量下从现象学上计算自旋极化观测值。该结果提供了在几个GeV碰撞能量下最新的STAR和HADES数据的见解，以及低能和高能碰撞之间的相似性和差异。更广泛地说，该项目成果有助于扩大我们在手性、涡度和磁场下的自旋量子输运的知识前沿，适用于不同学科的一般多体系统。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nuclear matter is at the heart of all visible matter in our universe. While it is known to be built from fundamental particles called quarks and gluons, precisely how the structures and properties of nuclear matter arise from the quarks and gluons remains a big question in fundamental physics. An important way to explore the question is through nuclear collision experiments, ongoing at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), that create a hot "subatomic soup" called quark-gluon plasma (QGP). This project helps understand the QGP by examining its behavior under extremely strong magnetic and vorticity fields. The PI accomplishes this by developing the theoretical description of QGP spin transport under such fields, performing phenomenological simulations to calculate observables, and analyzing the implications from comparison with experimental data. In addition to extracting QGP properties from such study, which is one of the major frontiers in today’s nuclear science, this project provides opportunities for engaging and mentoring graduate and undergraduate students in research as well as for carrying out a variety of public outreach activities. The objective of this project is to investigate novel transport arising from interplay between microscopic particle spin and macroscopic chirality, vorticity and magnetic fields of the bulk matter created in heavy ion collisions. The first component is to quantitatively understand the so-called chiral magnetic effect and associated background correlations. This is done by utilizing the anomalous-viscous fluid dynamics simulation framework, with an emphasis on analyzing the influence of initial nuclear structure inputs. The goal is to achieve an explanation of the latest high-precision isobar collision measurements as well as a coherent interpretation for the signal/background evolution from isobar to gold-gold collisions. The second component aims to advance the hydrodynamic framework with angular momentum as well as to phenomenologically compute spin polarization observables using a combination of hydrodynamic and transport models for a wide range of beam energies. The results offer insights into the latest STAR and HADES data at a few GeV collision energy as well as the similarity and difference between low and high energy collisions. More broadly, the project outcome helps expand our knowledge frontier on spin quantum transport under chirality, vorticity, and magnetic fields for general many-body systems across different disciplines.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.