RUI: Constraining the Symmetry Energy of Neutron-Rich Nucleonic Matter at Supra-Saturation Densities

East Texas A&M University, Commerce TX

Investigators

Abstract

Properties of neutron-rich nuclear matter are at the heart of many fundamental questions in nature. They are currently being explored experimentally by using a wide variety of advanced new facilities around the world. Most critical to understanding experimental observations of various novel phenomena using these facilities is the symmetry energy, which encodes the energy related to neutron-proton asymmetry in nuclear matter. The latter is a fundamental quantity currently under intense investigation in both nuclear physics and astrophysics. The density dependence of nuclear symmetry energy is a vital ingredient in describing the structure of neutron stars and neutron-rich nuclei and the dynamics of heavy-ion reactions. It also influences significantly the strain amplitude, frequency and damping time of gravitational waves from both rotating and oscillating neutron stars. Moreover, the high-density behavior of the symmetry energy is also closely connected to the possible non-Newtonian gravity at short distance due to either the geometrical effects of extra space-time dimensions or the exchange of new bosons predicted by super-symmetric extensions of the Standard Model of particle physics. However, our current knowledge about the nuclear symmetry energy especially at super-saturation densities is very poor. The ultimate goal of my work supported by this NSF grant is to determine the symmetry energy of dense neutron-rich nucleonic matter using nuclear reactions especially those induced by high energy rare isotope beams and to examine its impacts on astrophysics and cosmology. To realize this goal, effects of the tensor force, isospin dependence of the short-range nucleon-nucleon correlation function and spin-isospin dependence of the three-body force on the high-density behavior of the nuclear symmetry energy and their manifestations in nuclear reactions and neutron stars will be investigated. The proposed activities will have significant impacts on advancing our knowledge not only in nuclear physics but also in astrophysics and cosmology. Moreover, the PI will promote more close integration of research, teaching, training, and learning by involving proactively both graduate and undergraduate students in carrying out the proposed research. This project will help better prepare students to become next generation scientists and engineers. Furthermore, the project will further enhance the infrastructure and conditions for both research and education at Texas A&M University-Commerce.