Session L5: Bonner Prize Session

Tom W. Bonner Prize in Nuclear Physics Lecture: The limits of nuclear landscape

Understanding nuclei is a quantum many-body problem of incredible richness and diversity and studies of nuclei address some of the great challenges that are common throughout modern science. Nuclear structure research strives to build a unified and comprehensive microscopic framework in which bulk nuclear properties, nuclear excitations, and nuclear reactions can all be described. A new and exciting focus in this endeavor lies in the description of exotic and short-lived nuclei at the limits of proton-to-neutron asymmetry, mass, and angular momentum. In this talk, advances in the nuclear density functional theory will be reviewed in the context of the main scientific questions, experimental developments, and the advent of extreme-scale computing platforms.   

New Insights into the EMC Effect

Deep-inelastic scattering cross section ratios plotted as a function of the Bjorken scaling variable, xB, show an unexpected structure indicating that partonic structure in nuclei is different than in free nucleons. This phenomenon is commonly referred to as the EMC effect. Recent Jefferson Lab experimental data showed that the slope of the EMC effect in the 0.3 $<$ xB $<$ 0.7 scales as the local nuclear density rather than the average nuclear density. This result lead to the comparison of xB $>$ 1 short-range correlation plateaus versus the magnitude of the EMC effect slope, which shows a clear linear relation. In this talk, I will discuss the EMC effect and the short-range correlation plateaus and what this phenomenological relationship between the two implies.   

Microscopically-based energy density functionals for nuclei

A fundamental challenge of nuclear theory is to predict the properties of nuclei starting from the underlying vacuum two- and three-nucleon interactions. While impressive progress has been made in extending the limits of {\it ab initio} methods beyond the lightest nuclei, the nuclear energy density functional (EDF) approach is the only computationally feasible many-body method capable of describing nuclei across the mass table. Driven by interest in the coming generation of radioactive isotope beam facilities, along with studies of astrophysical systems such as neutron stars and supernovae that require controlled extrapolations of nuclear properties in isospin, density, and temperature, there is a large effort currently underway to develop nuclear energy functionals with substantially reduced global errors and improved predictive power away from stability. One possible path forward is to develop non-empirical EDFs that are more closely linked to the underlying nuclear Hamiltonian. In this talk, I describe how the interplay and coalescence of different threads: rapidly increasing computational power, effective field theory, renormalization group transformations, and density matrix expansion techniques are enabling the development of next-generation EDFs starting from realistic two- and three-nucleon interactions.