[en] This progress report and continuation proposal summarizes our achievements for the period from July 1, 1994 to September 30, 1995 and requests continued funding for our program in experimental medium-energy nuclear physics. The focus of our program remains the understanding of the short-range part of the strong interaction in the nuclear medium. In the past year we have focused our attention ever more sharply on experiments with real tagged photons, and we have successfully defended two new experimental proposals: Photofission of Actinide and Preactinide Nuclei at SAL and Photoproduction of the ρ Meson from the Proton with Linearly Polarized Photons at CEBAF. (We are co-spokespersons on two previously approved Hall-B experiments at CEBAF, Photoreactions on ³He and Photoabsorption and Photofission of Nuclei.) As part of the team that is instrumenting the Photon Tagger for Hall B; we report excellent progress on the focal-plane detector array that is being built at our Nuclear Detector Laboratory, as well as progress on our plans for instrumentation of a tagged polarized-photon beam using coherent bremsstrahlung. Also, we shall soon receive a large computer system (from the SSC) which will form the basis for our new Data Analysis Center, which, like the Nuclear Detector Laboratory, will be operated under the auspices of The George Washington University Center for Nuclear Studies. Finally, during the past year we have published six more papers on the results of our measurements of pion scattering at LAMPF and of electron scattering at NIKHEF and Bates, and we can report that nearly all of the remaining papers documenting this long series of measurements are in the pipeline

[en] This report reviews progress on our nuclear-physics program for the last year, and includes as well copies of our publications and other reports for that time period, The structure of this report follows that of our 1991 Renewal Proposal and Progress Report: Sec. II outlines our research activities aimed at future experiments at CEBAF, NIKHEF, and Bates; Sec. III gives results of our recent research activities at NIKHEF, LAMPF, and elsewhere; Sec. IV provides an update of our laboratory activities at GWU, including the acquisition of our new Nuclear Detector Laboratory at our new Virginia campus; and Sec. V is a list of our publications, proposals, and other reports. Copies of those on medium-energy nuclear physics are reproduced in the Appendix

[en] This renewal proposal requests continued funding for our program in experimental medium-energy nuclear physics. The focus of our program remains the understanding of the short-range part of the strong interaction in the nuclear medium. In the past three years we have focused our attention ever more sharply on experiments with real tagged photons at CEBAF. We are part of the Hall-B Collaboration at CEBAF. We are co-spokespersons on two approved CEBAF experiments, Photoreactions on ³He and Photoabsorption and Photofission of Nuclei, and we are preparing another, Nondiffractive Photoproduction of the ρ Meson with Linearly Polarized Photons, for presentation to the next CEBAF PAC. We are part of the team that is instrumenting the Photon Tagger and a high-energy tagged polarized-photon beam for Hall B; some of the instrumentation for these projects is being built at our Nuclear Detector Laboratory, under the auspices of The George Washington University Center for Nuclear Studies. Our recent measurements of pion scattering from ³H and ³He at LAMPF and of cluster knockout from few-body nuclei at NIKHEF have yielded very provocative results, showing the importance of the very light nuclei as a laboratory for quantifying important aspects of the nuclear many-body force. We look forward to expanding our studies of short-range forces in nuclei, particularly the very fight nuclei using electromagnetic probes and employing the extraordinary power of CEBAF and the CLAS

[en] This report discusses research done on the following topics: electron-scattering nuclear-structure studies; coincidence electrodisintegration studies of light nuclei; pion scattering and reactions on the three-body nuclei; and pion scattering from shell-model nuclei

[en] This report reviews progress on our nuclear-physics program for the last ten months, and includes as well copies of our publications and other reports for that time period. The structure of this report follows that of our 1992 Progress Report: Sec. II outlines our research activities aimed at future experiments at CEBAF, NIKHEF, and Bates; Sec. III gives results of our recent research activities at NIKHEF, LAMPF, and elsewhere; Sec. IV provides an update of our laboratory activities at GWU, including those at our new Nuclear Detector Laboratory at our Virginia Campus; and Sec. V is a list of our publications, proposals, and other reports. Copies of those on medium-energy nuclear physics are reproduced in the Appendix. The highlight of the year has been the approval by the NIKHEF and CEBAF PACs of all three of the proposals we have submitted. These are ''Recoil Polarization of the Neutron in the Reactions ³He(e,e'n) and ⁴He(e,e'n),'' NIKHEF Proposal 93-09, ''Photoreactions on ³He,'' CEBAF Proposal 93-044, and ''Photoabsorption and Photofission of Nuclei,'' CEBAF Proposal 93-019. The NIKHEF experiment involves the use of the High-Acceptance Recoil Polarimeter for detection and measurement of the polarization of the emitted neutron. We, together with our colleagues at Grenoble, are responsible for the design and construction of the wire chambers for this device; we have largely completed the design phase this past year. The CEBAF experiments involve the use of the Hall-B Photon Tagger for production of the monochromatic photon beam. We are responsible for the 432-scintillator focal-plane detector array for this device; again, most of the design work and some prototype testing have been completed this past year. In addition, we have continued to make progress on data analysis and publication of results of previous measurements at Bates, LAMPF, and NIKHEF

[en] This report discusses the following topics: electron-scattering nuclear-structure studies; coincidence electrodisintegration studies of light nuclei; pion scattering and reactions on the three-body nuclei; and pion scattering from shell-model nuclei

[en] This report reviews progress on our nuclear-physics program for the last ten months, and includes as well copies of our publications and other reports for that time period. The structure of this report follows that of our 1992 Progress Report: Sec. II outlines our research activities aimed at future experiments at CEBAF, NIKHEF, and Bates; Sec. III gives results of our recent research activities at NIKHEF, LAMPF, and elsewhere; Sec. IV provides an update of our laboratory activities at GWU, including those at our new Nuclear Detector Laboratory at our Virginia Campus; and Sec. V is a list of our publications, proposals, and other reports. Copies of those on medium-energy nuclear physics are reproduced in the Appendix. The highlight of the year has been the approval by the NIKHEF and CEBAF PACs of all three of the proposals we have submitted. These are open-quotes Recoil Polarization of the Neutron in the Reactions ³He(e,e') and ⁴He(e,e'n),close quotes NIKHEF Proposal 93-09 open-quotes Photoreactions on ³He,close quotes CEBAF Proposal 93-044, and open-quotes Photoabsorption and Photofission of Nuclei,close quotes CEBAF Proposal 93-019. The NIKHEF experiment involves the use of the High-Acceptance Recoil Polarimeter (HARP) for detection and measurement of the polarization of the emitted neutron. We, together with our colleagues at Grenoble, are responsible for the design and construction of the wire chambers for this device; we have largely completed the design phase this part year. The CEBAF experiments involve the use of the Hall-B Photon Tagger for production of the monochromatic photon beam. We are responsible for the 432-scintillator focal-plane detector array for this device; again, most of the design work and some prototype testing have been completed this past year

[en] This report reviews progress on our nuclear-physics program for the last year, and includes as well copies of our publications and other reports for that time period. The structure of this report follows that of our 1991 Renewal Proposal and Progress Report: Sec. II outlines our research activities aimed at future experiments at CEBAF, NIKHEF, and Bates; Sec. III gives results of our recent research activities at NIKHEF, LAMPF, and elsewhere; Sec. IV provides an update of our laboratory activities at GWU, including the acquisition of our new Nuclear Detector Laboratory at our new Virginia Campus; and Sec. V is a list of our publications, proposals, and other reports. copies of those on medium-energy nuclear physics are reproduced in the Appendix

[en] Angular distributions have been measured for the reaction ²⁵Mg(d,p)²⁶Mg, at a bombarding energy of 12.0 MeV, for states up to 6 MeV excitation in ²⁶Mg. Distorted-wave analysis has allowed extraction of l-value admixtures and spectroscopic strengths. Comparison is made with shell-model calculations

[en] The local-density approximation to the delta-hole model is investigated. Features learned from work on the momentum-space approach to the pion-nucleus optical potential are incorporated into the model. Preliminary calculations of pion elastic scattering with the modified model are in excellent agreement with data. The model provides a numerically efficient approach to studying delta dynamics in the nucleus