Advances in High Energy Nuclear Physics

在自然界的四种基本力量中，人们对强核力的了解最少。宇宙中许多重要的过程背后都有强大的力量。强核力的一个特别重要的方面是夸克胶子等离子体的存在。如果普通物质被加热到比太阳核心更热的约1,000,000,000度，原子和分子将不复存在，甚至原子核内的质子和中子也会融化。剩下的夸克和胶子的原始汤汁充满了非常早期的宇宙。人们可以在大粒子对撞机中通过相互撞击重原子核来重建夸克胶子等离子体。欧洲大型强子对撞机和美国相对论重离子对撞机的实验项目研究夸克胶子等离子体。PI和他的团队将开展研究，以提高我们对核碰撞中夸克胶子等离子体性质的理解。该项目将使用计算机模拟、机器学习和先进的统计方法来实现这一目标。它将为研究生和年轻的核科学科学家提供培训。通过使用与这些碰撞中的等离子体一起创建的探测器来研究核碰撞中的夸克胶子等离子体。其中最有希望的探测器是高能光子和喷射。光子具有夸克胶子等离子体对它们几乎透明的独特性质。因此，它们可以从产生的等离子体液滴的深处传递信息。然而，最先进的计算假设等离子体实际上对光子是完全透明的。这个项目试图量化在完全没有最终状态相互作用的假设下所产生的错误。这可以更好地理解有关光子的现有数据，这些数据显示出一些令人费解的特征。在探测器中，喷流被视为强子的准直喷雾，即夸克和胶子的束缚状态。它们是从单个能量非常高的夸克或胶子中出现的，这些夸克或胶子被分散在远离碰撞光束的轴线上。当喷流与周围的等离子体相互作用时，它们在时空和动量空间中以复杂的模式演化。这个项目将试图超越简单的时空图景，它受到经典传播的启发，经常被用来解释数据，通过观察这些喷流阵雨的等价物维格纳分布。最后，国际和平研究所将继续开发和探索“混合强子化”计算机代码。混合强子化是对核碰撞最后阶段夸克和胶子形成强子过程的一种新的模拟。申请将集中在喷气式飞机上，涉及来自等离子体的夸克和胶子与喷气式飞机中的夸克和胶子的重新组合。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。

Among the four fundamental forces in nature the strong nuclear force is understood the least. The strong force is behind many important processes in the universe. One particularly important aspect of the strong nuclear force is the existence of quark gluon plasma. If ordinary matter is heated up to temperatures of about 1,000,000,000,000 degrees, hotter than the core of the sun, atoms and molecules cease to exist and even protons and neutrons inside atomic nuclei melt. The remaining primordial soup of quarks and gluons is what filled the very early universe. One can recreate quark gluon plasma in large particle colliders by smashing heavy nuclei into each other. Experimental programs at the Large Hadron Collider in Europe and the Relativistic Heavy Ion Collider in the US study quark gluon plasma. The PI and his group will carry out research that will improve our understanding of properties of quark gluon plasma in nuclear collisions. The project will use computer simulations, machine learning, and advanced statistical methods to reach this goal. It will provide training for graduate students and young scientists in nuclear science.Quark gluon plasma in nuclear collisions is studied through the use of probes that are created together with the plasma in these collisions. Among the most promising probes are high energy photons and jets. Photons have the unique property that the quark gluon plasma is almost transparent to them. They can thus deliver information from deep inside the droplet of plasma that is created. However, state-of-the-art calculations assume that the plasma is actually perfectly transparent to photons. This project attempts to quantify the errors that are made with the assumption of a complete absence of final state interactions. This can lead to a better understanding of available data on photons which exhibits some puzzling features. Jets are seen in detectors as collimated sprays of hadrons, i.e. bound states of quarks and gluons. They emerge from a single, very energetic quark or gluon that has been scattered away from the axis of the colliding beams. Jets evolve in a complicated pattern in space-time as well as momentum space while they interact with the plasma around them. This project will try to go beyond the simple space-time picture, inspired by classical propagation, that is often utilized in the interpretation of data, by looking at the equivalent of Wigner distributions for these jet showers. Lastly, the PI will continue to develop and explore the "Hybrid Hadronization" computer code. Hybrid Hadronization is a novel simulation of the process of quarks and gluons forming hadrons in the last phase of nuclear collisions. Applications will focus on jets and involve the recombination of quarks and gluons from the plasma with those in jets.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.