Research in Low-Energy Nuclear Theory

Ohio State University, The, Columbus OH

Investigators

Abstract

The strong interaction is responsible for the binding of protons and neutrons into atomic nuclei. Improved quantitative understanding of how this happens is essential not only for fundamental nuclear research at US experimental facilities but for progress in astrophysics, for experiments on the nature of neutrinos, and for applications to energy and homeland security. The era of precision calculations of nuclear structure and reactions is underway, enabled in part by research findings and products from past NSF grants to the PI. New activities will include extending the range and capabilities of statistical methods for assessing theoretical uncertainties and for physics discovery, improving the extraction of information from experiment that minimally depends on model assumptions, and developing and testing a novel approach to systematically describing the full nuclear landscape. The training received by undergraduates, graduate students, and postdoctoral research associates in carrying out these activities contributes directly to the building of a diverse scientific workforce. The mix of analytical and numerical computation the students and postdocs must employ is excellent preparation for both academic and industrial research, which is validated by the strong track record of past members of the group. Projects are proposed in three major categories: Bayesian statistics for effective field theory (EFT) uncertainty quantification, calculation/extraction of process-independent quantities, and EFT for finite density nuclear systems. The Bayesian methods will be enabled by the extension of eigenvector continuation emulators and applied to inter-nucleon interactions, few- and many-body systems, and electroweak probes. Recent progress on the density matrix expansion and phase-space power counting for many-body calculations will be extended and a renewed attack on EFT for nuclear density functional theory will be made. Finally, the group will extend recent calculations of knock-out reactions from a renormalization group perspective, which exploits scale and scheme dependence in these reactions. Applications range from further treatments of short-range-correlation (SRC) physics relevant for JLab experiments and novel treatments of knock-out and other reactions for FRIB and astrophysics, including the consistent use of optical potentials for reactions involving heavy nuclei. These projects all contribute to the goal of microscopic, model-independent calculations of nuclei. All of these projects will impact forefront problems in low-energy nuclear physics as outlined in the Long Range Plan for Nuclear Science, such as the physics of nuclei far from stability, which is relevant for multi-messenger astrophysics and to FRIB. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.