Research in Strong-Interaction Theory

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

Title of Project: Research in Strong-Interaction Theory Principal Investigators: R. J. Furnstahl, B. C. Clark, S. Jeschonnek, R. J. Perry The study of a wide range of problems involving strongly interacting systems is proposed. The projects proposed fall into several broad categories, ranging from studies directly involving quark and gluon degrees of freedom, to effective theories of the strong interaction at low energies, to analyses of strong-interaction experiments. Intellectual merit: The transition from hadronic degrees of freedom to quark-gluon degrees of freedom will be studied though increasingly sophisticated models of quark-hadron duality and by investigating short-range structure in light nuclei through improved theoretical tools for disentangling the nuclear ground state information from coincidence electron scattering data. These projects have strong and direct ties to the experimental program at Jefferson Lab. Other projects revisit QCD sum rules, which exploit another facet of quark-hadron duality. The renormalization group tools developed in the light-front field theory program are largely redirected toward low-energy effective field theories. Effective theories of nuclear systems, which are governed by low-energy quantum chromodynamics (QCD), are being developed from two directions. From one side, fundamental work extending effective field theories (EFT) for nucleon-nucleon, three-body systems, and many-body systems is proposed. In parallel, from the other side, are projects to improve phenomenological descriptions of realistic nuclear systems to reduce model dependence. The efforts complement each other and both will impact forefront problems in nuclear physics, such as the study of nuclei far from stability. Renormalization group methods play important roles in each category. The goal of model independence is naturally coupled with the recognition of universal aspects of the physics, which in turn enhances interactions with other disciplines. Ongoing efforts to develop relativistic descriptions of a wide range of nuclear reactions and nuclear structure (e.g., global optical potential, nuclear densities, meson-nucleus scattering, inelastic reactions) will take advantage of EFT input. Reliable extractions of neutron densities will be made for more nuclei, and the optical potentials will be extended to higher energies and applied to studies of parity violation. Broader impacts: The training received by undergraduates, graduate students, and postdoctoral research associates in carrying out the proposed activities contributes directly to the building of a diverse scientific workforce. The mix of analytical and numerical computation our students and postdocs must employ is excellent preparation for both academic and industrial research. Activities funded by an REU supplement will actively involve undergraduates in research; all previous REU students in the group who have graduated are either working in industry, or business, or enrolled in professional or graduate school. The group is committed to diversity in science and has successfully mentored several members of under-represented groups, including four who have obtained faculty positions. Several proposed projects provide data to the Nuclear Data Center at Brookhaven National Laboratory. Direct benefits to society include the development of global optical potentials, which are being used to estimate cross sections that are important for understanding long-term radioactive waste storage, and calculations of nuclear cross sections, which are used in predicting dosimetry for patients in radiation therapy.