Hadronic and Nuclear Structure and Dynamics

对强相互作用的理解，即决定原子核结构的力，是粒子物理学标准模型中最具挑战性的问题之一，该模型描述了所有基本粒子的数量和性质。强相互作用的基本理论，以夸克和胶子的理论为基础，被称为量子色动力学（QCD），具有非常复杂的动力学，这导致了强子（重子，包括质子和中子，介子及其激发）的丰富性质，也导致了核相互作用和结构的复杂性。因此，挑战是多方面的，而且非常复杂。这些挑战需要各种各样的实验努力，以及理论努力。在此背景下，本项目将进一步发展量子cd基础理论与强子/核物理之间的联系。预期在这方面开发的工具和方法可能具有更广泛的应用领域。PI是杰斐逊实验室理论小组的联合任命者，为他提供了专注于杰斐逊实验室相关物理的机会。该项目的一项重要任务是汉普顿大学的研究生和本科生的教育和培训。该项目的另一个更广泛的影响将是PI与参与杰斐逊实验室实验的科学家的互动。本项目主要研究单强子和少核子的中低能强相互作用问题，以及QCD的一些基本问题。所使用的方法是基于被称为有效理论的强相互作用的严格描述，这与QCD一致，并利用实验和点阵QCD计算结果。其目的是提高QCD的理论知识和发展理论方法。更具体地说，在单强子中，将有两条主要的研究方向：1)在重子中发展和应用改进的手性有效理论，其中实现了低能和1/Nc展开（Nc是QCD中颜色自由度的数目）的结合；应用于重子观测，特别是在晶格QCD中得到的结果将被追求，其中特别是通过晶格QCD可获得的夸克质量依赖关系将被用于分析有效理论的收敛问题。特别强调的是涉及奇异性的重子的应用，由于奇异夸克的质量相对较大，在有效理论的实施方面仍然存在未解决的问题。这些研究对于提高从超子衰变中提取弱相互作用参数的准确性具有重要意义。2)在1/Nc展开的框架下研究激发态重子，主要目的是利用QCD的基本展开来组织重子共振的描述；本工作对目前各机构重子共振实验结果的分析有一定的影响，特别是杰弗逊实验室，也可应用于当前激发态重子谱的点阵QCD计算。在一些体物理中，研究的重点是应用手性有效理论和1/Nc展开来研究核子-核子相互作用。在量子光盘的基础方面，该项目将专注于纯胶动力学，使用全息量子光盘的方法研究其基本的非摄动量，即胶子凝聚和拓扑磁化率。

The understanding of the strong interactions, the force that determines the structure of atomic nuclei, is one of the most challenging problems in the Standard Model of particle physics, which describes the number and properties of all the elementary particles. The fundamental theory of the strong interactions, based on the theory of quarks and gluons known as Quantum Chromodynamics (QCD), has a very complex dynamics which gives rise to the rich properties of hadrons (baryons, including protons and neutrons, and mesons and their excitations) and also to the complexity observed in nuclear interactions and structure. The challenges are therefore many and very complex. Those challenges require a variety of experimental efforts, as well as theoretical efforts. In this context, this project will further develop the connection between the fundamental theory of QCD and hadronic/nuclear physics. It is expected that tools and methods developed in that context may have a broader domain of applications. The PI is a joint appointee in the Theory Group at Jefferson Lab, providing him with the opportunity to focus on Jefferson Lab related physics. An important mission of the project is the education and training at Hampton University of graduate and undergraduate students. An additional broader impact of the project will be the PI's interaction with scientists involved in Jefferson Lab experiments.This project focuses on low and intermediate energy strong interactions in single hadron and few nucleon problems, as well as some fundamental aspects of QCD. The methods used are based in rigorous descriptions of the strong interactions known as effective theories, which are consistent with QCD, and make use of experimental as well as lattice QCD calculations results. The aim is to advance the theoretical knowledge of QCD and the develop theoretical methods. More specifically, in single hadrons, two main lines of research will be pursued: 1) Development and applications of an improved chiral effective theory in baryons, where the combination of the low energy and the 1/Nc expansions (Nc is the number of color degrees of freedom in QCD) is implemented; applications to baryon observables, and in particular to results obtained in Lattice QCD for those observables will be pursued, where in particular the quark mass dependencies accessible through Lattice QCD will be utilized for analyzing issues of convergence of the effective theory. Particular emphasis will be on the applications to baryons involving strangeness, where there are still unresolved issues with the implementation of effective theories due to the relatively large mass of the strange quark. In particular, these studies have impact in for improving the accuracy of the extraction of weak interaction parameters from hyperon decays. 2) Study of excited baryons in the framework of the 1/Nc expansion, which has as main aim the use of that fundamental expansion of QCD to organize the description of baryon resonances; this work has an impact in the analysis of current experimental results on baryon resonances from various facilities, in particular Jefferson Lab, and it can also be applied to the current Lattice QCD calculations of the excited baryon spectrum. In few body physics, the research is focused on applying the combined chiral effective theory and 1/Nc expansion to study the nucleon-nucleon interaction. Among the fundamental aspects of QCD, the project will focus on pure glue-dynamics, studying its fundamental non-perturbative quantities, namely gluon condensate and topological susceptibility using methods of holographic QCD.