Benchmarking a Multi-Phase Transport for Relativistic Heavy Ion Collisions

相对论性重离子碰撞多相传输的基准测试

• 批准号: 2012947
• 负责人: Zi-Wei Lin
• 金额: $ 29.57万
• 依托单位: East Carolina University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012947&HistoricalAwards=false
• 关键词: Benchmarking; Multi; Phase; Transport; Relativistic

The soup of elementary particles, quarks and gluons, that characterized the universe for a few millionths of a second after the Big Bang, known as the quark-gluon plasma (QGP), has been created in high energy heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) in the USA and the Large Hadron Collider (LHC) in Europe. Such experiments allow physicists to study the QGP properties and understand the strong interaction at extreme temperatures and densities. A rich set of data has been measured from these experiments, including the recent evidence that the QGP is even formed in small collision systems. Hydrodynamics-based models as well as transport models have been quite successful in describing many observables. However, because transport models include non-equilibrium dynamics, they are expected to be different from hydrodynamic models for small systems. Open questions include the onset and origin of the observed collective motion of the produced particles from small to large systems, and how an interacting system transitions from the dilute limit to the hydrodynamic limit. This project focuses on using the improved transport method to address these questions, with the PI mentoring students in this research at both graduate and undergraduate levels. The improved multi-phase transport model as a public code also serves as a convenient event generator and testbed for the nuclear physics community.The main goal of this project is to address open questions regarding the QGP properties by improving the theoretical foundation and accuracy of a multi-phase transport model. This model contains a parton cascade phase and a bulk hadronization model in addition to fluctuating initial conditions and a later hadron cascade phase. The objectives include the following: i) benchmark and improve the accuracy of the parton transport method in describing the evolution of the dense matter; ii) improve the hadronization process, including starting the quark coalescence around a critical energy density instead of the parton kinetic freeze-out and applying fragmentation to heavy-flavor partons at high transverse momentum; iii) improve a multi-phase transport model with the verified parton cascade and improved hadronization and then make direct comparisons with experimental observables such as anisotropic flows. With the improved transport model constrained by bulk observables, properties of the dense matter such as the shear viscosity can also be quantitatively studied and compared with results from other approaches such as viscous-hydrodynamic models.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.

由基本粒子、夸克和胶子组成的汤，在宇宙大爆炸后几百万分之一秒的时间里是宇宙的特征，被称为夸克-胶子等离子体（QGP），是在美国的相对论重离子对撞机（RHIC）和欧洲的大型强子对撞机（LHC）的高能重离子碰撞中产生的。这样的实验使物理学家能够研究QGP的性质，并了解极端温度和密度下的强相互作用。从这些实验中获得了丰富的数据，包括最近的证据表明，QGP甚至是在小型碰撞系统中形成的。基于水动力学的模型以及输运模型在描述许多可观测物方面已经相当成功。然而，由于输运模型包括非平衡动力学，因此预计它们与小系统的水动力学模型不同。悬而未决的问题包括观察到的从小系统到大系统产生的粒子的集体运动的开始和起源，以及相互作用的系统如何从稀释极限过渡到流体动力极限。这个项目的重点是使用改进的交通方式来解决这些问题，PI在这个研究中指导研究生和本科生。改进的多相输运模型作为一种公共代码，也为核物理学界提供了一个方便的事件生成器和测试平台。该项目的主要目标是通过改进多相输运模型的理论基础和准确性来解决有关QGP性质的开放性问题。该模型除包含波动初始条件和后强子级联相外，还包含一个部分子级联相和一个体强子化模型。目标包括：1)检验和提高部分输运方法在描述致密物质演化过程中的准确性；Ii)改进强子化过程，包括在临界能量密度周围开始夸克聚并而不是部分子的动力学冻结，并在高横向动量下对重味部分进行碎片化；Iii)利用已验证的部分子级联和改进的强子化改进多相输运模型，然后与各向异性流动等实验观测结果进行直接比较。利用改进的输运模型，可以定量地研究致密物质的性质，如剪切粘度，并与其他方法（如粘度-流体动力学模型）的结果进行比较。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。

项目成果

Calculating QCD Phase Diagram Trajectories of Nuclear Collisions using a Semi-analytical Model

使用半解析模型计算核碰撞的 QCD 相图轨迹

• DOI: 10.1051/epjconf/202327601012
• 发表时间: 2023
• 期刊: EPJ Web of Conferences
• 作者: Mendenhall, Todd;Lin, Zi-Wei
• 通讯作者: Lin, Zi-Wei

Calculating the initial energy density in heavy ion collisions by including the finite nuclear thickness

• DOI: 10.1103/physrevc.103.024907
• 发表时间: 2020-12
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: T. Mendenhall;Zi-Wei Lin

Implication of two-baryon azimuthal correlations in pp collisions at LHC energies on the QGP

• DOI: 10.1016/j.physletb.2022.137063
• 发表时间: 2021-12
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Liuyao Zhang;Jinhui Chen;Wei Li;Zi-Wei Lin

Thermodynamics of partonic matter in relativistic heavy-ion collisions from a multiphase transport model

• DOI: 10.1103/physrevc.105.034912
• 发表时间: 2021-02
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Han-Sheng Wang;G. Ma;Zi-Wei Lin;Wei-jie Fu

Left-right splitting of elliptic flow due to directed flow in heavy ion collisions

• DOI: 10.1103/physrevc.106.054910
• 发表时间: 2021-09
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Chao Zhang;Zi-Wei Lin