Microscopic Properties of Hot and Dense QCD Matter

在早期宇宙冷却过程的几微秒后，一种极热的基本粒子(夸克和胶子)等离子体凝聚成被称为强子的束缚状态，强子是宇宙中可见物质的基石。夸克-胶子等离子体(QGP)的凝聚将夸克和胶子限制为强子，产生了约98%的可见质量。夸克禁闭和强子质量产生机制的发现是粒子和核物理基础研究的中心目标。在实验上，在相对论重离子对撞机和大型强子对撞机上，在实验室里，通过高能碰撞原子核，可以重新产生创纪录温度超过2万亿开尔文的QGP小液滴。然而，从测量的粒子光谱中推断QGP的性质及其强子化是非常具有挑战性的。PI将与他的研究生和合作者一起开发理论方法，并将它们应用于从实验数据中揭示QGP的基本性质。他的研究和教育活动还包括在德克萨斯A&A&M大学星期六早上物理项目中进行的本科生研究和对高中生的推广。重魅力和底夸克，以及电磁(EM)辐射，是对QGP特别有价值的探索。PI将使用最先进的强核力量子多体理论来分析重夸克的扩散(布朗运动)及其随后的强子化。对含有重夸克的重子(3夸克态)和介子(夸克-反夸克态)的实验光谱的系统分析将揭开强子化的机制，并在提取重夸克扩散系数方面提供前所未有的精度，重夸克扩散系数是表征QGP中相互作用强度的关键参数。PI将进一步利用可以穿透重离子碰撞形成的QGP的电磁辐射来分析质量产生的机制。他将研究强子化转变附近重子的光谱变化，并提取介质的另一个基本传输参数-电导率。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。

A few micro-seconds into the cooling process of the early Universe, an extremely hot plasma of elementary particles (quarks and gluons) condensed into bound states called hadrons, the building blocks of the visible matter in the Universe. The condensation of the quark-gluon plasma (QGP) confined the quarks and gluons into hadrons and generated about 98% of the visible mass. The discovery of the mechanisms of quark confinement and hadron mass generation are central goals of fundamental research in particle and nuclear physics. Experimentally, small droplets of QGP, at record temperatures exceeding 2 trillion Kelvin, can be re-created in the laboratory by colliding atomic nuclei at high energies, at the Relativistic Heavy-Ion Collider and the Large Hadron Collider. However, it is very challenging to infer the properties of the QGP and its hadronization from the measured particle spectra. The PI, together with his graduate students and collaborators, will develop theoretical methods and apply them to unravel fundamental properties of the QGP from experimental data. His research and educational activities also encompass undergraduate research and outreach to high-school students within the Saturday Morning Physics program at Texas A&M. The heavy charm and bottom quarks, as well as electromagnetic (EM) radiation, are particularly valuable probes of the QGP. The PI will use state-of-the-art quantum many-body theory of the strong nuclear force to analyze the diffusion of heavy quarks (Brownian motion) and their subsequent hadronization. A systematic analysis of the experimental spectra of baryons (3-quark states) and mesons (quark-antiquark states) containing heavy quarks will unravel mechanisms of hadronization and provide unprecedented precision in the extraction of the heavy-quark diffusion coefficient, a key quantity to characterize the interaction strength in the QGP. The PI will further use EM radiation, which can penetrate the QGP formed in heavy-ion collisions, to analyze the mechanism of mass generation. He will investigate the spectral modifications of baryons near the hadronization transition and extract the electric conductivity, another fundamental transport parameter of the medium.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.