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 structure
The 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.
