Connecting Parton Cascade to QCDS Shear Viscosity for a Dynamical Model of Finite Temperature Kinetic Theory

将 Parton Cascade 连接到 QCDS 剪切粘度以建立有限温度动力学理论的动态模型

• 批准号: 2310021
• 负责人: Zi-Wei Lin
• 金额: $ 27万
• 依托单位: East Carolina University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310021&HistoricalAwards=false
• 关键词: Connecting; Parton; Cascade; QCDS; Shear

Experiments involving high-energy heavy-ion collisions at world-leading accelerator facilities such as the Relativistic Heavy Ion Collider (RHIC) in the U.S. and the Large Hadron Collider (LHC) in Europe, are being used to study the constitutive blocks of extreme states matter at high density and temperature. Such studies provide insights regarding the properties of the Universe right after the Big Bang, when elementary particles such as gluons and quarks formed a state of matter known as the quark gluon plasma (QGP) or quark soup. This project will support the development of theory, models and simulations needed to improve our understanding of the QGP formation and its dynamical properties. The project will also support the training of students at the graduate and undergraduate levels. Under the PI’s mentorship the students will acquire practical and analytical skills that will serve them well in their future careers in academia or industry. The computer codes developed by the PI and their students are open source and will provide a testbed for future research for the benefit of the nuclear physics community.The main goal of this project is to develop the current ZPC parton cascade, which solves the nonlinear relativistic Boltzmann equation, into a dynamical model of finite temperature QCD kinetic theory. Currently ZPC only includes elastic scatterings and treats all flavors with the same two-gluon scattering cross section. In addition, its cross section is determined by a fixed screening mass throughout the parton evolution; this leads to a decrease of the ZPC eta/s with temperature, contrary to the results from pQCD or the Bayesian analysis of available experimental data. Making the screening mass temperature-dependent will lead to the correct temperature-dependence of eta/s. Leading-order inelastic parton processes will be included to describe the chemical equilibration, and flavor-dependent cross sections will be used to properly describe the plasma equilibration. After a determination of the accurate relationship between eta and the parton cross sections, the PI will adjust the screening masses to enable the parton cascade to match the expected QCD shear viscosity including its temperature dependence down to the QCD phase transition temperature.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.

美国相对论重离子对撞机（RHIC）、欧洲大型强子对撞机（LHC）等世界领先的加速器设施进行高能重离子对撞实验，用于研究极端状态的本构块这些研究提供了有关大爆炸后宇宙特性的见解，当时胶子和夸克等基本粒子形成了一种称为夸克胶子的物质状态。该项目将支持理论、模型和模拟的发展，以提高我们对 QGP 形成及其动力学特性的理解。该项目还将支持研究生和本科生的培训。在 PI 的指导下，学生将获得实践和分析技能，这将有助于他们未来在学术界或工业界的职业生涯。PI 及其学生开发的计算机代码是开源的，将为未来的研究提供一个测试平台。核物理的该项目的主要目标是将当前的 ZPC 部分子级联（解决非线性相对论玻尔兹曼方程）发展为有限温度 QCD 动力学理论的动力学模型，目前 ZPC 仅包含弹性散射，并用相同的两个来处理所有风味。 - 胶子散射截面，其截面是由整个部分子演化过程中固定的屏蔽质量决定的，这导致 ZPC eta/s 随温度降低，这与结果相反。可用实验数据的 pQCD 或贝叶斯分析将导致 eta/s 的正确温度依赖性，以描述化学平衡和风味依赖性交叉。在确定 eta 和部分子横截面之间的准确关系后，PI 将调整筛选质量以使部分子级联与预期的 QCD 剪切相匹配。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。