Quark-Gluon and Hadronic Degrees of Freedom in Few-Body Systems

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This research project investigates the transition from hadronic degrees of freedom to quark-gluon degrees of freedom in several systems, both nucleons and light nuclei. This will be done by investigating short-range structure in light nuclei on the one hand, and quark-hadron duality on the other hand. Both parts of the research program are immediately relevant to the experimental program at Jefferson Lab. This project will contribute to current research at a national facility, and provide training for students at The Ohio State University.Coincidence electron scattering from nuclei is the canonical tool for investigating short-range structures. Many properties of nuclei can be described in a picture containing only nucleons, deltas, and the lightest mesons. However, it is clear that when one proceeds to smaller distances, or higher energies and momenta used to explore the nuclei, one will find a situation where the relevant degrees of freedom are no longer the hadrons, but quarks and gluons. Appropriate theoretical tools for disentangling the nuclear ground state information from the data will be developed and tested, and suitable observables will be identified. I will also perform conventional nuclear physics baseline calculations for processes in which one expects to observe the onset of color transparency.Quark-hadron duality states that in certain kinematical regions, the proper average of hadronic observables is described by a perturbative QCD result. While this phenomenon is well established experimentally, a satisfying theoretical explanation of duality is still lacking. Modeling duality and studying how it arises in simple models is the most promising road to understanding duality. This project will continue this approach. I will focus on providing the necessary theoretical understanding for the highly promising applications of duality, which will allow for the extraction of deep inelastic information from resonance data.