Hadron Physics and Non-Perturbative QCD Modeling

这个研究项目解决了亚原子物理中被称为量子色动力学（QCD）的标准模型部分所描述的受限夸克和胶子的强相互作用的机制。我们基于QCD的Dyson-Schwinger方程实现了一种连续统非微扰方法，该方法保留了微扰QCD的短距离重整化群行为，而红外域由一个参数描述，以产生动态手性对称性破缺的经验量。后一种现象是宇宙中至少98%已知稳定物质质量的来源，它指导着我们理论方法的发展。这项工作将分析和解释由弗吉尼亚州纽波特纽斯杰斐逊实验室（JLab）产生的亚原子粒子的夸克和胶子结构的信息，并为目前正在进行的升级所预期的实验提供预测。这种类型的理论工作为世界各地亚原子物理实验室的一系列基础物理项目提供了信息和动力。具体的物理问题包括介子和介子的部分子分布，介子和介子的跃迁或广义部分子分布，介子在整个动量传递范围内的弹性和跃迁形式因子，以及对核子部分子分布及其比值的扩展。我们预计副产品将是对介子电荷形式因子从非摄动到摄动动力学转变的质量尺度的新理解。该计划的广泛影响包括核物理和粒子物理的交叉受精，JLab和RHIC实验设施的投资回报，以及通过研究生研究培训与本科教学相结合的研究和教育的整合。研究生与国内和国际知名科学家的互动是对国家研究和教育基础设施的贡献。PI使用这个研究项目中的例子来说明量子力学和核与粒子物理核心研究生课程的关键要素。PI为研究生和博士后主持一个非正式的研讨会课程，讨论和介绍QCD和本研究项目基础上的场理论。与海外同事的合作，有助加强科研和教育方面的国际合作。

This research project addresses mechanisms underlying the strong interaction of subatomic physics in terms of the confined quarks and gluons described by that part of the Standard Model known as Quantum Chromodynamics (QCD). We implement a continuum nonperturbative approach based on the Dyson-Schwinger equations of QCD which preserves the short distance renormalization group behavior of perturbative QCD while the infrared domain is described by one parameter to generate the empirical amount of dynamical chiral symmetry breaking. The latter phenomenon is the source for the generation of at least 98% of the mass of known stable matter in the universe, and it guides the development of our theoretical methods.This work will analyze and interpret information about the quark and gluon structure of sub-atomic particles produced by the Jefferson Laboratory at Newport News Virginia (JLab), and provide predictions for the experiments anticipated from the upgrade currently being undertaken. Theoretical work of this type informs and motivates a portfolio of fundamental physics programs at sub-atomic physics laboratories across the world. Specific physics issues addressed include parton distributions of the pion and kaon mesons, the transition or generalized parton distributions of the pion and kaon mesons, the elastic and transition form factors of pions for a complete range of momentum transfer, and an extension to nucleon parton distributions, and their ratios. We anticipate a by-product will be a new understanding of the mass scale for transition from non-perturbative to perturbative dynamics in the pion charge form factor. Broader impacts of the program include the cross-fertilization of nuclear and particle physics, a return on the investment in the experimental facilities at JLab and RHIC, and integration of research and education through the research training of graduate students in connection with undergraduate teaching. The interactions of graduate students with scientists who are prominent nationally and internationally is a contribution to the nation's infrastructure for research and education. The PI uses examples from this research program to illustrate key elements of core graduate classes in Quantum Mechanics and Nuclear and Particle Physics. The PI supervises an informal seminar course for graduate students and postdoctoral associates to discuss and present aspects of QCD and field theory that underly this research program. The collaboration with overseas colleagues will enhance international cooperation in science research and education.