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B=4N Nuclei in the Skyrme Model


Type

Thesis

Change log

Authors

King, Christopher 

Abstract

The Skyrme model enables us to approximate nuclei via topological solitons known as Skyrmions. The B = 4 Skyrmion is of particular importance as its symmetry and stability means that multiple B = 4 Skyrmions can combine with each other to form larger B = 4N Skyrmions. In this thesis we investigate the properties of these B = 4N Skyrmions and compare them with results found in the wider nuclear physics community. We go beyond rigid body quantization and develop a formalism of using vibrational quantisation to generate the energy spectrum of the Oxygen−16 nucleus. The Oxygen−16 nucleus is treated as an arrangement of four B = 4 Skyrmions, whose dynamics enable us to create a 2−dimensional manifold of B = 16 configurations. We solve the Schrödinger equation on this manifold and discover new states previously not found in the B = 16 sector of the Skyrme model. We compare these states with those found experimentally and find that there is a excellent it to the energy spectrum. In order to apply vibrational quantization to a wider range of nuclei we create a novel approximation for Skyrmions and the interactions between them. By generating Skyrmions with Gaussian sources we find analytic expressions for the pion fields and interaction energies of Skyrmions, with particular focus on the B = 1 and B = 4 Skyrmions, and show how this could be applied to vibrational quantization and the clustering of B = 4 Skyrmions. B = 4N nuclei are the only nuclei with zero spin and isospin, which means that their electric charge density is proportional to their baryon density. This simplification makes these nuclei particularly susceptible to investigation via electron scattering. We develop a classical averaging method to calculate the Patterson function and the form factor for a B = 4N nucleus and make comparisons with experimental data. We also discover a way of using the baryon density directly to approximate the locations of zeroes and stationary points of the form factor.

Description

Date

Advisors

Manton, Nick

Keywords

Skyrmions, Vibrational Quantisation, Nuclear Interactions

Qualification

Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge