The Study of Intermediate Energy Photonuclear Physics with Polarized Beams and Targets

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This award will support continued study of the properties of the nucleon through the production of mesons and nucleon resonances.The dominant component of this program isthe use of polarization observables in photonuclear reactions. The experimental program is located at the Laser Electron Gamma Source (LEGS) atthe National Synchrotron Light Source (NSLS) at Brookhaven NationalLaboratory (BNL). Combining our novel polarized HD target, SPHICE, and thelarge acceptance SASY detector with the high quality polarized photon beamat LEGS, the initial experimental program concentrates on sum-rulemeasurements of the spin-dependent Compton amplitude for the nucleon toprovide a direct determination of the forward spin-polarizability andGerasimov Drell-Hearn sum rule integrals for the proton and the first suchmeasurement for the neutron. We will simultaneously measure the doublepolarization observables for pion photoproduction from the proton andneutron. The combination of SPHICE and SASY at LEGS makes measurement of acomplete set of observables possible, permitting the first model independentmultipole analysis. High quality double polarization data on thephotodisintegration of deuterium will also be obtained greatly expanding ourunderstanding of this fundamental reaction. The JMU group is responsible for producing the high purity HD gasrequired for the production of the polarized targets used for theseexperiments, the operation and mapping of the the superconducting magnet tobe installed as part of the SASY upgrade, and will participate in thecollection and analysis of the data. Five undergraduate students willparticipate in this project each year and gain experience in both on-campusand off-campus activities.