RUI: Studies of Nucleon Structure Using Electromagnetic Probes at Jefferson Lab

核子、质子和中子都是由更基本的夸克组成的，这一点现在已是公认的事实。该基金支持的主要物理学项目旨在研究质子的结构。 更具体地说，我们在杰斐逊实验室从质子中散射电子来测量质子的电磁特性。 我们的团队通过设计新的实验，建造先进的粒子探测器以及开发新的分析和建模软件来参与这些工作。我们通过为本科生和研究生提供有意义的实质性项目来吸引学生。我们小组长期建立的实验计划体现了杰斐逊实验室的主要使命：阐明质子、中子和介子的基本结构。我们专注于实验，这将进一步我们了解的夸克自旋结构的质子在非微扰制度。杰斐逊实验室最近完成了能量为12 GeV的电子束的升级，我们的团队现在准备利用增加的物理范围。我们继续努力将质子电磁形状因子比的测量扩展到杰斐逊实验室可能的最高动量传递，并研究核介质内这种形状因子比的可能修改。这些实验将为现有的质子结构理论模型提供严格的检验，并将成为发展基于量子色动力学（QCD）的更先进模型的强大动力。

It is now a well-established fact that nucleons, protons and neutrons, are made up of more elementary particles called quarks. The main physics program supported by this grant aims to study of the structure of the proton. More specifically, we scatter electrons from protons at Jefferson Laboratory to measure the electric and magnetic properties of the proton. Our group is involved in these efforts through the design of new experiments, the construction of advanced particle detectors, and the development of novel analysis and modeling software. We involve students by providing meaningful, substantive projects to both undergraduate and graduate students. Our group's long established program of experiments embody Jefferson Lab's primary mission: to elucidate the underlying structure of protons, neutrons, and mesons. We focus on experiments which will further our understanding of the quark spin structure of the proton in the non-perturbative regime. Jefferson Lab has recently completed an upgrade to electron beams of energy 12 GeV, and our group is now poised to take advantage of the increased physics reach. We continue to lead the efforts to extend the measurement of the proton electromagnetic form factor ratio to the highest momentum transfers possible at Jefferson Lab, and also investigate the possible modification of this form factor ratio within the nuclear medium. These experiments will provide severe tests of the available theoretical models of proton structure, and will serve as a strong impetus for the development of more advanced models based upon quantum chromodynamics (QCD).