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

• 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

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，随着结合它们的力被热能淹没，它往往会分解成更多的元素颗粒。 例如，虽然液态水是由松散结合的水分子收集的，但蒸汽是未结合的水分子的气体。同样，当加热原子核时，核会经历相变并溶解成更元素的夸克和胶子。这发生在大约两万亿开尔文温度下。 所得的系统称为Quark-Gluon等离子体（QGP）是自然界中最热，最稠的物质，它是有史以来最低的特定粘度最低的最“完美的液体”。在过去的二十年中，高能核核核核核物理学界一直在研究这一原始物质的研究，通过实验性地在相对论的重离子碰撞中创建它，并通过深入的理论研究与两个相对论的重离子界面（相对性重离子碰撞者）了解其特性。和欧洲（大型强子对撞机），对QGP的实验已经超出了发现阶段的远远超出了精度测量阶段。在过去的二十年中，我做出了一致的努力，从理论上讲，在相对论重离子碰撞中创建的QGP从几个阶段中演变出来。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。多年来，我的小组已经成功地对QGP进行了如此全面的研究，该研究使用了从量子场理论到流体动力模拟的广泛理论工具。在这项赠款建议中，我建议在我们的成功分析和预测计划中添加重要的新物理元素QGP现象学使用我们的流体动力学和JET-QGP相互作用模拟工具（此处的“ JET”是指高能量夸克或Gluon）。首先，通过正确考虑胶子的光束方向动力学，将对初始状态计算进行严重改进。 其次，我们将调查令人惊讶的现象，即即使是由质子 - 核碰撞创建的较小系统也表现出QGP流体的证据，特别是考虑到完全考虑到有限尺寸效应的射流光谱的修饰。 第三，我们将对辐射和电磁信号的非平衡校正进行研究。最后，我们将使用可用的贝叶斯统计工具来以系统的方式确定QGP的属性，例如传输系数。通过如此全面而彻底的研究，我们将能够以精确而决定性的方式对QGP进行表征。