Chiral Dynamics in the Nucleon Quark Sea

现代核物理学的一个重要探索是从理论上理解核子（质子和中子）的夸克、反夸克和胶子结构，量子色动力学（QCD）的自由度，强相互作用的基本理论。在这个项目中，研究者和他的学生将推进必要的理论发展，以了解在托马斯杰斐逊国家实验室，布鲁克海文国家实验室和其他设施世界各地的实验。除了为现有和未来的实验项目提供理论支持外，该项目的好处还包括对研究生的培训。该项目还将为本科生提供研究机会，在理论核子结构研究的前沿。该项目将探讨核子结构的横向动量依赖部分子分布函数（TMD）。基于量子色动力学因式分解的TMD是研究高能反应的有效工具。当没有最终状态的横动量被解决时，与描述过程的熟悉的和更好的共线部分子分布函数相比，TMD提供了关于动力学的详细信息。他们提供访问部分子轨道运动和自旋轨道相关性方面时，偏振光束和目标进行了探讨。这个项目的目标是推进目前的理解的属性TMD在一个非微扰框架。该项目的具体目标是：（1）在低初始尺度下确定TMD的非微扰性质，（2）识别手征对称性破缺的模型无关特征，重点是海夸克效应，（3）探索唯象学应用并为实验提供预测。在这个项目中使用的工具包括微扰演化方程，动力学模型和有效的手征理论。

An important quest in modern nuclear physics concerns the theoretical understanding of the structure of nucleons (protons and neutrons) in terms of quarks, antiquarks and gluons, the degrees of freedom of quantum chromodynamics (QCD), the fundamental theory of strong interactions. In this project, the investigator and his students will advance the development of theory necessary to understand experiments at the Thomas Jefferson National Laboratory, Brookhaven National Laboratory, and other facilities world-wide. In addition to providing theoretical support for existing and future experimental programs, the benefits of this project include training for graduate students. The project will also offer research opportunities for undergraduate students at the frontiers of theoretical nucleon structure research.This project will explore nucleon structure in terms of transverse momentum dependent parton distribution functions (TMDs). Based on a QCD factorization formalism, TMDs are a useful tool in the study of high-energy reactions. As compared to the familiar and better known collinear parton distribution functions which describe processes when no final-state transverse momenta are resolved, TMDs offer detailed information about dynamics. They provide access to parton orbital motion and aspects of spin-orbit correlations when polarized beams and targets are explored. The goal of this project is to advance the current understanding of the properties of TMDs in a non-perturbative framework. The specific objectives of the project are: (1) determine the non-perturbative properties of TMDs at a low initial scale, (2)identify model-independent signatures of chiral symmetry breaking with focus on sea quark effects, (3) explore phenomenological applications and present predictions for experiments. The tools employed in this project include the use of perturbative evolution equations, dynamical models, and effective chiral theories.