Investigations in Intermediate Energy Spin Physics

该提案将支持杰弗逊实验室的三个高评价实验的开发、建设和执行。这些实验包括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弗逊实验室C大厅进行，将使用相同的实验装置，并且很可能会背靠背地进行。实验使用GEP-III合作项目构建的大接收度BigCal光谱仪、HMS光谱仪和UVA极化NH3和LiD靶。我们小组计划建造一个Lucite Cerenkov hodoscope，这对背景拒绝和跟踪至关重要。该小组还将参与实验软件的开发工作、模拟、数据采集和数据分析。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上的自旋不对称性，其中价夸克占主导地位，因此是研究核子自旋结构的相对干净的区域。测量的自旋观测值是理解该区域QCD的基础。QCD是量子场论，在量子理论的框架中描述了夸克之间以及质子和中子之间的强相互作用的性质。RCS实验将测量真实康普顿散射的初始状态螺旋度相关不对称性，统计精度为0.1。康普顿散射是指具有一定能量的伽马射线光子在穿过物质时被电子反弹，并看到它们的能量下降。这一测量结果将大大增加我们将GPD方法应用于实际光子诱导的反应的信心。广义部子分布（GPD’s）将著名的费曼部子分布和核子的电磁形状因子扩展到新的运动维度。在正向极限下，这些分布减小为费曼部分分布。另一方面，GPD的第一阶矩给出了电磁形状因子。一般来说，GPD比常规观测值包含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的核子自旋风味（夸克类型）结构的认识。对极化夸克分布矩的认识的提高将为理论模型和晶格QCD提供严格的检验。北卡罗来纳农工州立大学是一所历史悠久的黑人大学。90%的学生是非裔美国人。传统上，这些学生在物理专业的代表性不足。这项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重大影响。在过去的几年里，该组织支持和监督了20多名学生，其中大多数是非洲裔美国人。

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.