Investigations in Intermediate Energy Spin Physics

这项提案将支持杰斐逊实验室三个高评级实验的开发、建设和执行。其中包括SANE实验E03-109、实验E05-101和半SANE实验E04-113。所有三个实验都将在杰斐逊实验室C厅进行，将使用相同的实验装置，并且很可能会背靠背运行。实验使用了由GEP-III合作建造的大接受BigCal光谱仪、HMS光谱仪和UVA偏振NH3和LID靶。我们的团队计划建造一台Lucite Cerenkov望远镜，这对背景拒绝和跟踪至关重要。该小组还将参与实验软件开发、模拟、数据获取和数据分析。我们的学生，其中大多数是少数民族学生，将在所有这些任务中发挥主要作用。SANE实验测量了质子在大x处的包含性自旋不对称性，在那里价夸克占主导地位，因此是一个相对干净的区域来研究核子的自旋结构。测量的自旋观测值是理解该区域QCD的基础。QCD是在量子理论框架下描述夸克之间以及质子与中子之间强相互作用性质的量子场论。通过RCS实验测量，初态螺旋度关联不对称性在实际康普顿散射中的统计精度为0.1。康普顿散射是指一定能量的伽马射线光子在电子穿过物质时会反弹，并看到它们的能量减少。这项测量将大大增强我们将GPD方法应用于由真实光子引起的反应的信心。广义部分子分布(GPD‘s)将著名的Feynman部分子分布和核子电磁形状因子推广到新的运动学维度。在前向极限下，这些分布简化为费曼部分子分布。另一方面，GPD的一阶矩给出了电磁形状因子。一般而言，GPD包含了比常规观测更丰富的核子结构信息。最后，来自半SANE的精确数据将显著提高我们对价夸克和海夸克核子自旋的味道(夸克类型)结构的了解。对极化夸克分布矩的了解的提高将为理论模型和晶格QCD提供严格的测试。北卡罗来纳农工大学是一所历史上的黑人大学(HBCU)。90%的学生是非裔美国人。传统上，这些学生在物理课上的代表性偏低。拟议的研究计划将为他们提供独特的实验核物理研究机会，因此将对他们的培训和教育产生强烈影响。在前几年，该组织支持和监督了20多名学生，其中大多数是非裔美国人。

This proposal will support the development, construction and execution of three highly rated experiments at Jefferson Lab. These include The SANE experiment E03-109, experiment E05-101, and the semi-SANE experiment E04-113. All three experiments will be conducted Jefferson Lab-Hall C, will use the same experimental setup and in all likelihood will run back to back. The experiments use the large acceptance BigCal spectrometer constructed by the GEP-III collaboration, the HMS spectrometer and the UVA polarized NH3 and LiD targets. Our group plans to build a Lucite Cerenkov hodoscope which is critical for background rejection and tracking. The group will also participate in the experiment software development effort, simulation, data taking and data analysis. Our students, the majority of whom are minority students, will play a major role in all these tasks. The SANE experiment measures inclusive spin asymmetries on the proton at large x, where valence quarks dominate and hence a relatively clean region to study the spin structure of the nucleon. The measured spin observables are fundamental for understanding QCD in that region. QCD is the quantum field theory that describes the properties of the strong interactions between quarks and between protons and neutrons in the framework of the quantum theory. The RCS experiment will measure, the initial state helicity correlation asymmetry in real Compton scattering to a statistical accuracy of 0.1. Compton Scattering is when gamma ray photons of a certain energy will bounce off electrons as they pass through matter, and see their energy decrease. The measurement will significantly increase our confidence in the application of the GPD approach to reactions induced by real photons. The generalized parton distributions (GPD's) extend the well-known Feynman parton distribution and electromagnetic form factors of the nucleon to new kinematic dimensions. In the forward limit, these distributions reduce to the Feynman parton distributions. On the other hand, the first moment of GPD's give the electromagnetic form factors. In general, the GPD's contain much richer structural information of the nucleon than conventional observables.Finally, precision data from the semi-SANE will significantly improve our knowledge of the flavor (type of quark) structure of the nucleon spin for both valence and sea quarks. The improved knowledge of the moments of the polarized quark distributions will provide stringent tests for theoretical models and Lattice QCD.North Carolina A&T State University is a historically black university (HBCU). Ninety percent of the student population is African American. These students have been traditionally underrepresented in physics. The proposed research program will provide them with unique research opportunities in experimental nuclear physics, and therefore will have a strong impact on their training and education. During previous years the group supported and supervised over twenty students most of whom were African Americans.