Investigations in Intermediate Energy Spin Physics

中能自旋物理研究

• 批准号: 0758095
• 负责人: Samuel Danagoulian
• 金额: $ 45万
• 依托单位: North Carolina Agricultural & Technical State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0758095&HistoricalAwards=false
• 关键词: Investigations; Intermediate; Energy; Spin; Physics

The NC A&T State University Nuclear Physics group is contributing to three major experiments at Jefferson Laboratory: 1) The SANE experiment, E07-003; 2) experiment E-07-011, ?A High Precision Measurement of the Deuteron Spin-Structure Function g1d/F1d?; and 3) the experiment E05-101, ?Initial State Helicity Correlation in Wide Angle Compton Scattering? RCS. All three experiments explore the spin structure functions of proton and deuterium. 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 generalized parton distributions (GPD) approach to reactions induced by real photons. The 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. All three experiments will be conducted in Hall C, and will use the same experimental setup. The NC A&T group has built and is in charge of the Lucite Hodoscope, a major component of the experimental setup. The group is also building the quartz hodoscope for the SuperHMS spectrometer needed for the Hall C 12 GeV upgrade in Hall C. North Carolina A&T State University is a historically black university (HBCU). The proposed research program will provide our students with unique research opportunities in experimental nuclear physics, and therefore will have a strong impact on their training and education. The program will allow them to work in a state-of-the-art facility and interact with scientists from other nationally recognized universities. In this respect this proposal can be very effective in attracting African Americans and other underrepresented groups to advanced degrees in physics and engineering and therefore will contribute to greater diversity in the field of nuclear physics.

北卡罗来纳州州立大学核物理小组正在杰斐逊实验室进行三项主要实验：1）SANE实验，E07-003; 2）实验E-07-011，？氘核自旋结构函数g1 d/F1 d？的高精度测量（3）E05-101、？广角康普顿散射中的初态螺旋度关联？RCS。这三个实验都探索了质子和氘的自旋结构函数。SANE实验测量了质子在大x处的自旋不对称性，其中价夸克占主导地位，因此是一个相对干净的区域来研究核子的自旋结构。测量到的自旋观测量是理解该区域QCD的基础。QCD是在量子理论框架内描述夸克之间以及质子和中子之间强相互作用性质的量子场论。RCS实验将测量真实的康普顿散射中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会从电子上反弹回来，并看到它们的能量减少。该测量将显著增加我们对广义部分子分布（GPD）方法应用于由真实的光子引起的反应的信心。GPD将著名的费曼部分子分布和核子的电磁形状因子扩展到新的运动学维度。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。一般来说，GPD的包含更丰富的结构信息的核子比传统的可观测量。所有三个实验将在C厅进行，并将使用相同的实验装置。NC A T小组已经建立并负责Lucite Hodoscope，这是实验装置的主要组成部分。该小组还在C厅为C厅12 GeV升级所需的SuperHMS光谱仪建造石英振速计。北卡罗来纳州AT州立大学是一所历史悠久的黑人大学（HBCU）。拟议的研究计划将为我们的学生提供实验核物理学独特的研究机会，因此将对他们的培训和教育产生重大影响。该计划将允许他们在最先进的设施中工作，并与来自其他国家认可的大学的科学家进行互动。在这方面，这项建议可以非常有效地吸引非裔美国人和其他代表性不足的群体攻读物理学和工程学高级学位，因此将有助于核物理学领域的更大多样性。