Date of Award

Spring 5-15-2019

Author's School

Graduate School of Arts and Sciences

Author's Department

Physics

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

The nucleon self-energies of 40Ca, 48Ca, and 208Pb are determined using a

nonlocal dispersive optical model (DOM). By enforcing the dispersion relation

connecting the real and imaginary part of the self-energy, both experimental

scattering data and nuclear structure data are used to constrain these

self-energies. The ability to calculate both bound and scattering states

simultaneously puts these self-energies in a unique position to consistently

describe exclusive knockout reactions such as (e,e'p). Using the

well-constrained self-energy describing 40Ca, the distorted-wave impulse

approximation (DWIA) description of the (e,e'p) reaction is shown to be valid

for outgoing proton kinetic energies around 100 MeV. This analysis also reveals

the importance of high-energy proton reaction cross section data in

constraining spectroscopic factors of the (e,e'p) reactions. In particular, it

is imperative that high-energy proton reaction cross section data are measured

for 48Ca in the near future so that the quenching of the spectroscopic factor

in the 48Ca(e,e'p)47K reaction can be properly constrained using the DOM.

Moreover, DOM generated spectral functions indicate that the quenching of

spectroscopic factors is due not only to long-range correlations, but also

partly due to the increase in the proton high-momentum content in 48Ca on

account of the strong neutron-proton interaction. Single-particle momentum

distributions of protons and neutrons in 48Ca and 208Pb calculated from these

spectral functions confirm this by clearly showing that neutron excess causes a

higher fraction of high-momentum protons than neutrons. In addition to proton

reaction cross section data, high-energy neutron total cross section data are

also shown to constrain the distribution of neutrons in these nuclei, leading

to the prediction of thick neutron skins in both 48Ca and 208Pb. Using the DOM

spectral functions, the binding energy density of each nucleus is calculated.

These energy densities call into question the degree to which the equation of

state for nuclear matter is constrained by the well-known empirical mass

formula.

Language

English (en)

Chair and Committee

Willem H. Dickhoff

Committee Members

Mark Alford, Lee Sobotka, Robert Charity, Saori Pastore,

Comments

Permanent URL: https://doi.org/10.7936/en1m-vp71

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