The Study of Nuclear Physics with Intermediate Energy Probes

虽然普通物质质量的98%是由强核力引起的，但目前对这种力的理论（量子色动力学）仍然没有完全理解。 该奖项支持通过探索物质的子结构来研究强核力。 原子的几乎全部质量都集中在它的微小的原子核中，原子核由带正电（质子）或电中性（中子）的核子组成。 然而，这些亚原子粒子并不是基本粒子，它们本身是由夸克通过胶粒子（胶子）结合在一起而形成的复合物体。核子的结构是强核力的表现，这是已知的最强的力。 这项研究将有助于推进核物理的发现和理解，并促进教学，培训和学习。 初级科学家的准备在所支持的活动中起着核心作用，南卡罗来纳州大学（USC）的核物理研究计划主要以位于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地。 在那里，该小组使用高能电子和光子束沿着复杂的粒子探测器，这些探测器部分是在南加州大学开发的，作为研究亚原子世界的强大显微镜。 该小组还在瑞士的Paul Scherrer研究所准备MUSE实验。 这个实验将通过从质子上散射μ子和电子来解决质子半径之谜。 通过探测器的开发、模拟、复杂实验的管理和数据分析，他们将揭示一些最深刻的问题，比如：核子的结构是什么？ 什么是以及我们如何激发它的内部自由度？ 一旦被激发，核子会以何种方式衰变回它的原始状态？ 如果核子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我们深入了解了强力的本质，并允许对基本理论进行严格的测试。

Although ninety-eight percent of the mass of ordinary matter is due to the strong nuclear force, the present theory of that force (Quantum Chromodynamics) is still not fully understood. This award supports the study of the strong nuclear force by probing the substructure of matter. Almost the entire mass of an atom is concentrated in its tiny nucleus, which is made of nucleons that 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 glue particles (gluons). The structure of nucleons is a manifestation of the strong nuclear force, which is the strongest force known. This research will help advance discovery and understanding in nuclear physics, and promote teaching, training, and learning. The preparation of junior scientists plays a central role in the supported activities.The nuclear physics research program at the University of South Carolina (USC) is mainly based at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. There, the group uses high-energy electron and photon beams along with sophisticated particle detectors that were developed, in part, at USC as powerful microscopes to study the subatomic world. The group is also preparing the MUSE experiment at the Paul Scherrer Institute in Switzerland. This experiment will address the proton-radius puzzle by scattering muons and electrons off the proton. Through detector development, simulations, management of complex experiments, and data analyses, they will shed light on some of the most profound questions like: What is the structure of the nucleon? What are and how can we excite its internal degrees of freedom? Once excited, in which way does the nucleon decay back to its original state? 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.