Topics in QCD Modeling of Hadron Physics

本文从夸克和胶子的束缚态出发，研究了强子物理的机制。 这里使用的特殊方法是一个非微扰模型的强子和强子过程的基础上戴森-Schwinger方程的基本场论。 当通过高能散射和电子束的显著反冲来探测亚原子粒子的亚结构时，它具有特别的优势;相对论的要求，重要的对称性破缺，以及夸克和胶子的不可观测性很容易被纳入。 场论的既定微扰行为也被保留。 这项研究将扩大这种方法的现有范围，并通过对一些主题的探索来批判性地审视短期行为。 这些包括夸克质量的依赖性，通过魅力夸克区域的观察，和分析格QCD结果的中间元素，如夸克传播子和夸克胶子顶点。 夸克-胶子顶点的改进描述是主要的兴趣，因为它控制着对常见的阶梯-彩虹近似的修正。 π电荷形状因子让位于微扰行为的动量尺度也是主要的兴趣。 其他主题包括从全QCD晶格模拟分析夸克传播子，使用代数模型来估计核子磁矩的奇异夸克含量，并探索对阶梯彩虹近似的高阶修正，介子结构观测值的夸克质量依赖性，重夸克介子的辐射跃迁，以及从夸克流关联中提取非微扰物理。 该计划的更广泛影响包括核物理和粒子物理的交叉施肥，亚原子科学实验设施的投资回报，研究和教学的一体化，以及科学成果的广泛传播。 从事该项目的博士生通过本科实验室或复习课的教学为本科教育做出了贡献。 我们促进博士生和经验丰富的研究人员之间的互动，作为对国家研究和教育基础设施的贡献。 PI使用这个研究项目的例子来说明量子力学和核与粒子物理学的核心研究生课程的关键要素。 PI和一位同事监督研究生和博士后同事的非正式研讨会课程，讨论和介绍QCD和场论的各个方面，这些方面在研究生课程之外，但仍然是前沿研究的核心。 PI还积极参与当地本科物理课程的重组;特别感兴趣的是新生研讨会课程的发展，以讨论物理学和相关科学的发现和突破的时事。

The mechanisms underlying hadron physics in terms of bound states of quarks and gluons are investigated. The particular approach used here is a nonperturbative modeling of hadrons and hadronic processes based on the Dyson-Schwinger equations of the underlying field theory. It hasparticular advantages when the substructure of subatomic particles is probedby the high energy scattering and significant recoil of beams of electrons; the demands of relativity, important broken symmetries, and the non-observation of quarks and gluons are easily incorporated. Established perturbative behavior of the field theory is also preserved. This research will extend the current reach of such an approach, and critically examine short-comings, through an exploration of a number of topics. These includethe quark mass dependence of observables up through the charm quark region, and an analysis of lattice-QCD results for intermediate elements, such asquark propagators and quark-gluon vertices. An improved description of the quark-gluon vertex is of primary interest since it controls the corrections to the common ladder-rainbow approximation. The momentum scale at which the pion charge form factor gives way to perturbative behavior is also of majorinterest. Other topics include an analysis of quark propagators from full-QCD lattice simulations, the use of an algebraic model to estimate the strange quark content of the magnetic moment of the nucleon and toexplore high order corrections to ladder-rainbow approximation, the quark mass dependence of meson structure observables, radiative transitions of heavy quark mesons, and the extraction of nonperturbative physics from quark current correlations. Broader impacts of the program include the cross-fertilization of nuclear and particle physics, a return on the investment in the experimental facilities of subatomic science, integration of research and teaching, and wide dissemination of scientific results. PhD students working on this project contribute to undergraduate education through their teaching of undergraduate laboratory or recitation sections. We foster interactions between the PhD students and experienced researchers as a contribution to the nation's research and education infrastructure. 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 and a colleague supervise an informal seminar course for graduate students and postdoctoral associates to discuss and present aspects of QCD and field theory that are outside graduate coursework but nevertheless central to cutting edge research. The PI is also active in a re-structuring of the local undergraduate physics curriculum for majors; a particular interest is the development of a freshman seminar course to discuss current events of discovery and breakthrough in physics and related science.