Hadron-Hadron Interactions and Exotic States using Lattice QCD with the Stochastic LapH Method

质子和中子组成原子核，由称为夸克和胶子的基本粒子组成，它们的相互作用由量子色动力学(QCD)描述。这一理论表明，自然界中许多其他类型的复合粒子，即强子，应该以不稳定共振的形式存在。因此，这个项目将使QCD预测的激发强子共振的性质的研究成为可能，使用大规模计算资源。了解这种共振将有助于我们深入了解强子和原子核内部发挥作用的关键物理机制。这项拟议的研究为目前的实验提供了支持，例如托马斯·杰斐逊国家加速器设施(JLab)D厅的GlueX实验。另一个焦点将是涉及一个被称为德尔塔重子的特定强子的散射。对德尔塔重子如何与其他粒子相互作用的详细确定，将对研究中微子的实验至关重要。中微子是一种弥漫在宇宙中的重要基本粒子。PI将指导一名从事这项研究的研究生，该研究生还将接受使用最先进的并行计算资源的培训。我们将使用时空格子上涉及夸克场和胶子场的路径积分的蒙特卡罗估计来研究激发强子和强子-强子相互作用的物理学。设计用来探测奇异状态的量子算符，如胶球、带有激发胶子的强子和四夸克，将被用来探索量子色动力学中激发态的性质。还将计算pion-pion、kaon-pion、核子-pion、核子-核子以及核子-超子散射相移，从而获得有关强子结构的重要信息。新的计算技术，如随机LAPH方法，使得在晶格QCD中进行这样的计算成为可能，这涉及到估计多强子和激发态算符的时间关联矩阵。涉及三角洲重子的形式因素将是一个特别关注的问题，因为它们对基于加速的中微子实验至关重要，例如地下深层中微子实验(DUNE)。这一奖项反映了NSF的法定任务，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。

Protons and neutrons, which make up atomic nuclei, are comprised of fundamental particles known as quarks and gluons, whose interactions are described by quantum chromodynamics (QCD). This theory suggests that many other types of composite particles, known as hadrons, should exist in Nature as unstable resonances. As such, this project will make possible a study of the properties of excited hadronic resonances as predicted by QCD, using large-scale computing resources. Understanding such resonances will help us gain insight into the key physical mechanisms at work inside hadrons and nuclei. The proposed research lends support to current experiments, such as the GlueX experiment in Hall D at the Thomas Jefferson National Accelerator Facility (JLab). Scattering involving one particular hadron known as a Delta baryon will be another focus. Detailed determinations of how the Delta baryon interacts with other particles will be crucial for experiments studying neutrinos, an important elementary particle that permeates the universe. The PI will mentor a graduate student engaged in this research, and the graduate student will also receive training in the use of state-of-the-art parallel computing resources. The physics of excited hadrons and hadron-hadron interactions will be studied using Monte Carlo estimates of path integrals involving quark and gluon fields on a space-time lattice. Quantum operators designed to probe exotic states, such as glueballs, hadrons with excited gluons, and tetraquarks, will be used to explore the nature of the excited states in quantum chromodynamics. Pion-pion, kaon-pion, nucleon-pion, nucleon-nucleon, and nucleon-hyperon scattering phase shifts will also be computed, yielding important information on hadron structure. New computational techniques, such as the stochastic LapH method, have made possible such computations in lattice QCD, which involve estimating temporal correlation matrices of multi-hadron and excited-state operators. Form factors involving the Delta baryon will be a particular focus since they are crucial to accelerated-based neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE).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.