Topics in Strong Force

了解核子的内部结构——质子和中子，我们最熟悉的物质的组成部分——是核物理学的基本挑战之一。这个项目将为量子色动力学（QCD）提供新的认识，量子色动力学描述了构成核子的夸克和胶子之间的强作用力。该项目将运用理论方法建立现象学模型，用于理解托马斯·杰斐逊国家加速器设施（JLab）从实验中获得的实验数据，这些实验主要集中在核子性质的测量上。最近JLab的12 GeV升级将使科学家能够以前所未有的精度研究QCD的特性。教育部分是这个项目的一个重要方面。对研究生和本科生的培训和指导将为未来在工业界或学术界的职业生涯做好准备。PI的外展活动将通过科普讲座以及对高中生的指导和指导来提高公众对核粒子物理的认识。这个项目的两个研究领域与强作用力的物理学有关，并基于广义的夸克约束问题的现象学和理论方法。该项目的第一个重点是了解对准概率分布敏感的过程的高扭转/阶修正，即广义Parton分布（gpd），这对于正确分析实验数据是必不可少的。PI和他的学生将开发一种分离技术，通过提供光子电产生截面的微分截面的方位矩的解析公式，从数据中分离出gpd。第二个推动力以最大超对称杨-米尔斯理论为中心，它占据了杨-米尔斯理论的谐振子地位，是解决强耦合QCD的核心尝试。在两种理论中具有非常相似的微扰展开的规范散射振幅是当前规范动力学分析方法的重点。建立一种允许人们非摄动地处理散射振幅的形式化方法的关键一步是它们在可适用于分析技术的零多边形轮廓上的威尔逊环的对偶描述。

Understanding the internal structure of nucleons -- protons and neutrons, the building blocks of matter that is most familiar to us -- is one of the fundamental challenges in nuclear physics. This project will contribute new understanding to Quantum Chromodynamics (QCD), the theory describing the strong force between the quarks and gluons making up the nucleon. The PI will apply theoretical methods to build phenomenological models used to understand experimental data obtained at the Thomas Jefferson National Accelerator Facility (JLab) from experiments focused on measurements of nucleon properties. The recent 12 GeV upgrade at JLab will allow scientists to study the properties of QCD with an unprecedented level of precision. The educational component represents an important aspect of this project. The training and mentoring of graduate and undergraduate students will prepare junior researchers for future careers in industry or academia. The PI's outreach activities will increase public awareness of nuclear-particle physics through popular science presentations, as well as by mentoring and guidance of high school students.The two research areas of this project are related to the physics of the strong force and are based on phenomenological and theoretical approaches to the problem of quark confinement, broadly defined. The first thrust of the project is focused on understanding of higher twist/order corrections to processes sensitive to quasiprobability distributions, known as Generalized Parton Distributions (GPDs), and will be indispensable for proper analysis of experimental data. The PI and his students will develop a separation technique to disentangle GPDs from data by providing analytical formulas for azimuthal moments of differential cross sections of photon electroproduction cross sections. The second thrust is centered around maximally supersymmetric Yang-Mills theory, which took on the status of the harmonic oscillator of Yang-Mills theories and is central in attempts to solving QCD at strong coupling. Understanding gauge scattering amplitudes, which possess very similar perturbative expansions in the two theories, is the focus of the currently pursued analytical approach to gauge dynamics. A crucial step in establishing a formalism that allows one to address scattering amplitudes nonperturbatively is their dual description in terms of Wilson loops on null polygonal contours that are amenable to analytical techniques.