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。虽然已知它是由被称为夸克和胶子的基本粒子构成的，但核物质的结构和性质是如何从夸克和胶子中产生的，这在基础物理学中仍然是一个大问题。探索这一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，创造出一种被称为夸克-胶子等离子体(QGP)的热“亚原子汤”。这个项目通过研究QGP在极强的磁场和涡度场下的行为来帮助理解QGP。PI通过发展这些场下QGP自旋输运的理论描述，执行唯象模拟来计算可观察到的量，并从与实验数据的比较中分析其含义，从而实现了这一点。除了从这种研究中提取QGP性质，这是当今核科学的主要前沿之一，这个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外联活动的机会。这个项目的目标是研究在重离子碰撞中产生的宏观手性、涡度和磁场与微观粒子自旋之间的相互作用所产生的新的输运。第一个组成部分是定量地理解所谓的手征磁效应和相关的背景关联。这是通过利用反常-粘性流体动力学模拟框架完成的，重点分析了初始核结构输入的影响。目标是实现对最新的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/背景演化的一致解释。第二个部分旨在推进具有角动量的流体动力学框架，以及使用大范围束流能量的流体动力学和输运模型的组合，从现象学的角度计算自旋极化观测值。这些结果提供了几个GeV碰撞能量下恒星和冥王星的最新数据，以及低能量和高能量碰撞之间的相似和不同之处。更广泛地说，项目成果有助于扩大我们在手性、涡度和磁场下跨不同学科的一般多体系统的自旋量子输运方面的知识前沿。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.