The Study of Nuclear Physics with Intermediate Energy Probes

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。几乎一个原子的全部质量都集中在它微小的原子核上。原子核是由带正电（质子）或电中性（中子）的核子构成的。然而，这些亚原子粒子并不是基本粒子，它们本身是由夸克组成的复合物体，夸克通过强作用力通过胶粒子（胶子）的交换而结合在一起。质子和中子的特性是地球上最强的力的表现。目前关于这种力的理论是量子色动力学。我们在南卡罗来纳大学的研究项目以弗吉尼亚州纽波特纽斯的托马斯·杰斐逊国家加速器设施为基础。在那里，我们使用高能电子束和光子束以及复杂的粒子探测器作为强大的显微镜来研究亚原子世界。我们试图回答这样的问题：核子的结构是什么？我们如何激发它的内部自由度？如果核子被嵌入致密的核物质中，它的结构会改变吗？对这些性质的实验研究使人们对强作用力的本质有了深入的了解，并允许对基本理论进行严格的测试。我们的项目为年轻的研究人员提供科学培训，并通过我们对光子和电子束用于放射治疗的理解，使医学物理界受益。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Almost the entire mass of an atom is concentrated in its tiny nucleus. The atomic nucleus is made of nucleons, which are either positively charged (protons) or electrically neutral (neutrons). These subatomic particles, however, are not elementary but are themselves composite objects made of quarks held together by the strong force via the exchange of glue particles (gluons). The properties of protons and neutrons are a manifestation of that strongest force on Earth. The present theory of that force is Quantum Chromodynamics. Our research program at the University of South Carolina is based at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. There, we use high-energy electron and photon beams along with sophisticated particle detectors as powerful microscopes to study the subatomic world. We try to answer questions like: What is the structure of the nucleon? What are and how can we excite its internal degrees of freedom? Does the structure of the nucleon change if it is embedded in dense nuclear matter? The experimental study of these properties gives insight into the nature of the strong force and allows for rigorous tests of the underlying theory. Our program provides scientific training to young researchers and also benefits the medical physics community through our understanding of the use of photon and electron beams for radiotherapy.