Precision Electromagnetic Studies of the Structure of Nuclei and

在理解原子核结构中迫切的问题是关联的作用、动力学相对论效应、原子核中核子结构的改变以及显式夸克自由度的出现。加州州立大学洛杉矶分校(CSLA)的中间能量小组建议使用电磁探测器对这些问题进行研究。在重核中，对于费米能级附近的壳层，理论计算表明需要存在长程关联。然而，在轻质量核中，短程核子-核子关联更为重要。这项实验工作将在托马斯·杰斐逊国家加速器设施(TJNAF)进行，并将包括与A厅和C厅合作安排或批准的实验。CSLA小组将集中大部分精力领导一个预定的实验(E06-007)，该实验旨在测量长程关联和相对论对铅区核态结构的影响。它还将通过监督分配给该实验的博士生和硕士研究生(S)对实验数据的分析，致力于实验的成功完成。它在这次大电流运行中对铅靶的经验将有助于它继续为另一项高强度铅实验开发目标，即确定核中子半径。CSLA小组将领导一项经批准的实验，以确定在高动量和能量转移下氦的质子敲除反应中的响应函数。这项实验将提供基准数据，可以与包括相对论结构在内的当前和新的核结构模型进行比较。来自这项测量的信息还将解决核介质对核子结构可能产生的影响的问题。这种对极大动量缺失的测量也可能揭示原子核结构中夸克自由度的开始。CSLA小组将参与实验，以确定质子的电磁结构向大动量转移，并明确测量双光子对e-p相互作用的贡献。在之前的资助期间，该小组在之前的暑假期间在杰斐逊实验室派驻了一名本科生，帮助组装热量计。CSLA的研究生将协助安装、执行和分析实验。作为杰斐逊实验室合作小组的成员，该小组还将参与它感兴趣的其他精选核子和核实验。该小组在高光度低温靶的设计、建造、调试和评估方面发挥了领导作用。CSLA小组将继续特别重视让学生参与其实验研究计划，包括有意义的方式，包括研究生、本科生和选定的高中生和教师。这一努力与他们领导的外展项目相协调，这些项目涉及当地拥有大量少数民族学生的高中。过去，学生和教师在适当的数据分析、MS论文的撰写和蒙特卡洛模拟方面都取得了丰硕的成果，CSLA的学生也成为已发表研究的合著者。他们将继续在这里提议的新实验中发挥重要作用，包括提交女士论文。

Pressing questions in the understanding of nuclear structure are the role of correlations, dynamical relativistic effects, modifications of nucleon structure in the nucleus and the onset of explicit quark degrees of freedom. The intermediate energy group at California State University, Los Angeles (CSLA) proposes a study of these questions using the electromagnetic probe. In heavy nuclei for shells near the Fermi energy theoretical calculations indicate the need for the presence of long-range correlations. However, in light mass nuclei short range nucleon-nucleon correlations are more important. The experimental work will be carried out at the Thomas Jefferson National Accelerator Facility (TJNAF) and will consist of experiments scheduled or approved in conjunction with the Hall A and Hall C collaboration.The CSLA group will focus most of its efforts on leading a scheduled experiment (E06-007) on the measurement of long-range correlations and the effect of relativity on the structure of nuclear states in the lead region. It will also commit to the successful completion of the experiment by supervising the experimental data analysis by the PhD and MS student(s) assigned to this experiment. Its experience with the lead target in this high current run will assist it in its continuing target development for another high intensity lead experiment, namely the determination of a nuclear neutron radius The CSLA group will lead an approved experiment to determine the response function in proton knockout reactions from helium at high momentum and energy transfer. This experiment would provide benchmark data against which current and new models of nuclear structure including relativistic structure can be compared. Information from this measurement will also address the question of possible nuclear medium effects on the nucleon's structure. This measurement carried out to extremely large missing momentum may also reveal the onset of quark degrees of freedom in nuclear structureThe CSLA group will participate in experiments to determine the electromagnetic structure of the proton to a large momentum transfer and explicitly measure two-photon contributions to the e-p interaction. The group stationed an undergraduate student during previous summers at Jefferson Lab in the previous grant period to assist in the assembly of the calorimeter. Graduate students from CSLA will assist in the installation, execution and analysis of the experiment.As members of Jefferson Lab collaborations the group will also be involved in other select nucleon and nuclear experiments in which it has a strong interest. The group has played a leading role in the design, construction, commissioning and evaluation of high luminosity cryogenic targets.The CSLA group will continue to place special emphasis on involving students in its experimental research program, including graduate, undergraduates and selected high school students and teachers in a meaningful way. This effort is coordinated with outreach programs they are leading involving local area high schools that have large populations of minority students. Students and teachers have been fruitfully engaged in appropriate data analysis, writing of a MS thesis and Monte Carlo simulations in the past, and CSLA students have appeared as co-authors on published research. They will continue to be significantly involved in the new experiments being proposed here, including submission of MS. theses.