Nuclear Structure and Reactions from Lattice Effective Field Theory

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Quantum Chromodynamics (QCD) is the theory of strong interactions, the fundamental force in nature that manifests itself by interactions between the building blocks of protons and neutrons that form the nuclei of atoms. Theoretical studies of QCD are central to nuclear physics efforts that seek a better understanding of the fundamental processes taking place in the Universe, processes that ultimately impact life on Earth. In this project, the PI will develop new theoretical and numerical techniques for calculating time-dependent quantities, in particular the nuclear reaction rates important for the development of astrophysical models of how nuclei interact to generate the fundamental elements that appear in the periodic table. Knowing these rates gives insight into the physics of the early universe and the nuclear reactions that produce the energy in stars. Broader impacts of this project include training of graduate students in numerical and analytical work for an academic or industry career benefiting society.This project builds on the adiabatic projection method for lattice EFT that was previously introduced by the investigator using funds from a U.S. National Science Foundation grant. Typical low energy reactions involve interactions between two atomic nuclei. The adiabatic projection method allows an effective two-body description of the participating nuclei starting from a microscopic description of the nuclei themselves in terms of several protons and neutrons. These ideas are developed further, here, in several ways. Mixed channel reactions are calculated that are important in describing inelastic processes. Reactions involving electromagnetic radiation would be calculated. Long-range interaction between nuclei due to the Coulomb force would be studied. Key reactions involving light nuclei that are relevant in Big Bang Nucleosynthesis and stellar burning would be studied. Some of these reactions play an important role in interpreting experimental results probing physics beyond the Standard Model of particle physics. These calculations would complement similar efforts in the field of halo nuclei. These nuclei are described as a tightly bound core with usually one or two valence neutrons forming a halo. This research ties in with planned major U.S. investment in rare isotope beam experiments.