Improving the Dispersive Optical Model toward a Dispersive Self-energy Method

Abstract

OF THE DISSERTATION Improving the Dispersive Optical Model toward a Dispersive Self-energy Method by Seth Waldecker Doctor of Philosophy in Physics Washington University in St. Louis, 2011 Professor Willem H. Dickhoff, Chairperson The connection between the dispersive optical potential and the irreducible nucleon self-energy from Green’s function theory is improved, providing a tighter link between nuclear reactions and nuclear structure. In particular, since the self-energy is inherently nonlocal, an explicitly nonlocal term is incorporated in the real part of the dispersive optical potential, which has been assumed to be local in previous parametrizations. The explicit treatment of nonlocality allows for a proper solution of the Dyson equation, and the resulting propagator can then be used to calculate experimental observables associated with ground state properties, such as the charge density, particle number, and the energy per particle. Comparison of these quantities with data suggests additional ways in which the dispersive optical model can be improved. For example, a better treatment of short-range correlations is needed, and explicitly including the nonlocality of the imaginary potential appears to be necessary for particle number conservation. Comparison of the dispersive optical potential with microscopic calculations of the self-energy is also made and suggests further improvements. Thus, increasing the correspondence between the potential from the dispersive optical model and the self-energy increases the amount of feedback from theory and experiment and provides a method for systematically improving the description of the empirical self-energy for both stable and rare isotopes. The dispersive optical model is also applied to transfer reactions, which are proving to be a useful tool for studying the nuclear structure of rare isotopes.