Study of hot and dense nuclear matter in relativistic heavy ion collisions

相对论性重离子碰撞中热致密核物质的研究

基本信息

批准号：
SAPIN-2018-00024
负责人：
Jeon, Sangyong
金额：
$ 6.19万
依托单位：
McGill University
依托单位国家：
加拿大
项目类别：
Subatomic Physics Envelope - Individual
财政年份：
2022
资助国家：
加拿大
起止时间：
2022-01-01 至 2023-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762498
关键词：
Study hot dense nuclear matter

项目摘要

When temperature increases, it tends to break up matter into more elemental particles as the forces binding them get overwhelmed by thermal energy. For instance, while liquid water is made of collection of loosely bound water molecules, steam is a gas of unbound water molecules. Likewise, when atomic nucleus is heated, the nucleus undergoes a phase transition and dissolves into more elemental quarks and gluons. This occurs at around two trillion kelvin temperature. The resulting system called Quark-Gluon Plasma, or QGP, is the hottest and the densest matter ever observed in nature and it is the most "perfect fluid'' with the lowest specific viscosity ever observed.In the past two decades, high energy nuclear physics community has been focusing on the study of this primordial matter by experimentally creating it in relativistic heavy ion collisions and understanding its properties through in-depth theoretical investigations. With two relativistic heavy ion colliders in operation in the USA (the Relativistic Heavy Ion Collider) and Europe (the Large Hadron Collider), experiments on QGP has moved on well beyond the discovery phase to the precision measurement phase. Theoretical analysis of this strongly interacting QCD (Quantum Chromodynamics) many-body system is an important testing ground for our understanding of strong nuclear interaction.In the past two decades, I have made a concerted effort to theoretically understand this primordial matter. QGP created in relativistic heavy ion collisions evolves through several stages. Although QGP phase is the most important stage, understanding the whole picture is crucial in extracting the properties of QGP from experimental data. My group has been successfully conducting such a comprehensive study of QGP for many years using wide range of theoretical tools from quantum field theory to hydrodynamic simulations.In this grant proposal, I propose to add important new physics elements to our successful program of analyzing and predicting QGP phenomenology using our hydrodynamics and jet-QGP interaction simulation tools (a "jet" here refers to a high-energy quark or gluon). First, the initial state calculation will be critically improved by properly taking into account the beam-direction dynamics of gluons. Second, we will investigate the surprising phenomenon that even smaller systems created by proton-nucleus collisions exhibit evidence of QGP fluid, in particular focusing on the modification of the jet spectra fully taking into account the finite size effect. Third, we will carry out studies on the non-equilibrium corrections to the hadronic and electromagnetic signals. Lastly, we will use available Bayesian statistics tools to determine the properties of QGP such as transport coefficients in a systematic way. Through such a comprehensive and thorough study, we will be able to characterize QGP in a precise and decisive manner.

当温度升高时，它往往会将物质分解成更多的元素粒子，因为结合它们的力会被热能压倒。例如，液态水是由松散结合的水分子集合而成，而蒸汽是未结合的水分子的气体。同样，当原子核被加热时，原子核会发生相变并溶解成更多的元素夸克和胶子。这种情况发生在大约二万亿开尔文温度下。由此产生的系统称为夸克-胶子等离子体（QGP），是自然界中迄今为止观察到的最热、密度最大的物质，也是迄今为止观察到的具有最低比粘度的最“完美流体”。在过去的二十年中，高能核物理学界一直致力于研究这种原始物质，通过在美国运行的两台相对论重离子对撞机进行实验，并通过深入的理论研究来了解其性质。（相对论重离子对撞机）和欧洲（大型强子对撞机），QGP 的实验已经远远超出了发现阶段，进入了精密测量阶段，对这种强相互作用的 QCD（量子色动力学）多体系统进行了理论分析。在过去的二十年里，我一直在努力从理论上理解这种在相对论性重离子碰撞中产生的原始物质经过几次演化。阶段。尽管 QGP 阶段是最重要的阶段，但了解整个情况对于从实验数据中提取 QGP 的特性至关重要。我的小组多年来一直使用从量子场论到流体动力学模拟的广泛理论工具，成功地对 QGP 进行了如此全面的研究。在这项拨款提案中，我建议在我们成功的分析和预测计划中添加重要的新物理元素使用我们的流体动力学和射流-QGP 相互作用模拟工具的 QGP 现象学（这里的“射流”指的是高能夸克或胶子）。首先，通过适当考虑胶子的束流方向动力学，初始状态计算将得到重大改进。其次，我们将研究令人惊讶的现象，即即使由质子-核碰撞产生的更小的系统也表现出 QGP 流体的证据，特别是在充分考虑有限尺寸效应的情况下，重点关注射流光谱的修改。第三，开展强子和电磁信号的非平衡修正研究。最后，我们将使用可用的贝叶斯统计工具系统地确定 QGP 的属性，例如传输系数。通过这样全面、透彻的研究，我们将能够准确、果断地描述QGP的特征。