The Study of Nuclear Physics with Intermediate Energy Probes

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Our research program at the University of South Carolina is based at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. There, we use high-energy electron and photon beams along with sophisticated particle detectors as powerful microscopes to study the subatomic world. We try to answer questions like: What is the structure of the nucleon? What are and how can we excite its internal degrees of freedom? Once excited, in which way does the nucleon decay back to its original state? Does the structure of the nucleon change if it is embedded in dense nuclear matter? Do other subatomic particles change their properties if they are produced in dense nuclear matter? The experimental study of these properties gives insight into the nature of the strong force and allows for rigorous tests of the underlying theory.Almost the entire mass of an atom is concentrated in its tiny nucleus. The atomic nucleus is made of nucleons, which are either positively charged (protons) or electrically neutral (neutrons). These subatomic particles, however, are not elementary but are themselves composite objects made of quarks held together by the strong force via the exchange of glue particles (gluons). The structure of nucleons is a manifestation of that strongest force known to mankind. Although ninety-eight percent of the mass of ordinary matter is due to the strong force, the present theory of that force (Quantum Chromodynamics) is still not fully understood. This research will help to advance our understanding. The preparation of junior scientists plays a central role in the supported activities.