Polarized Electron Scattering from Nucleons and Nuclei

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This grant supports the research of the Hadronic Physics group at the College of William and Mary. The group conducts experiments using the polarized electron beam available at the Thomas Jefferson National Accelerator Facility. These experiments utilize the minute violation of "mirror symmetry" in electron scattering, which occurs due to the presence of the weak neutral-current interaction, an otherwise unnoticeable contribution to the scattering process. This "parity-violation" technique is being used to probe the quark structure of protons and neutrons, to study the distribution of neutrons in a heavy nucleus (which has important implications for understanding neutron stars), and to search for possible new forces or new particles beyond those in the Standard Model of particle physics. The group is responsible for the design, construction and testing of large wire-chamber detectors required for the latter experiment, the equipment for which has been funded by an NSF Major Research Instrumentation grant.The grant supports 1.5 postdoctoral fellows and three graduate students. Substantial involvement of undergraduate students is also anticipated through senior research projects and the REU site program at William and Mary.