Linearly polarised pion photoproduction on the deuteron

Mullen, Christopher Andrew (2020) Linearly polarised pion photoproduction on the deuteron. PhD thesis, University of Glasgow.

Abstract

Measurements of the linear polarisation asymmetry in pion photoproduction on both the proton and neutron have been performed with a liquid deuterium target using the Mainzer Microtron and Crystal Ball detector at the Johannes Gutenberg Universität in Mainz. These results, particularly the π 0 n channel, provide current models attempting to describe the nucleon resonance spectrum and properties with essential constraints. Measurements on the neutron are essential to determine isospin amplitudes of the nucleon resonance spectrum. The experiment featured a photon beam polarised through coherent bremsstrahlung of a 1.5 GeV electron beam on an aligned diamond radiator. The target was cryogenic liquid deuterium cooled to 23 K. Detection of the produced π 0 s was achieved through their dominant decay to two photons which were subsequently recorded in high density scintillating crystal calorimeters, known as the Crystal Ball and TAPS. The same detectors were used to determine the direction of the recoiling proton or neutron while thin plastic scintillator was used to distinguish between the two nucleons. Results on the proton are consistent with previous measurements and predictions from groups performing partial wave analysis to determine the resonance properties. Results on the neutron are measured for the first time in this energy regime spanning the first and second resonance regions and favour the SAID partial wave analysis solution.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Hadron, nuclear, photoproduction, deuteron, polarisation.
• Subjects: Q Science > Q Science (General); Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Ireland, Professor David
• Date of Award: 2020
• Depositing User: Dr Christopher Andrew Mullen
• Unique ID: glathesis:2020-80265
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 10 Mar 2020 09:50
• Last Modified: 14 Sep 2022 08:25
• Thesis DOI: 10.5525/gla.thesis.80265
• URI: https://theses.gla.ac.uk/id/eprint/80265