Polarisation observables in neutral pion photoproduction with MAMI

Gardner, Simon (2016) Polarisation observables in neutral pion photoproduction with MAMI. PhD thesis, University of Glasgow.

Abstract

This thesis presents new high statistics measurements of polarisation observables in neutral pion photoproduction from experiments carried out with the Crystal Ball at the Mainzer Microtron (MAMI) in Mainz. The polarisation observable Σ has been measured in the γp → π0 p reaction in the region between the ∆(1232) and second resonance region. Measurements of observables Σ, I s and I c in the γp → 2π0 p reaction have been made from the 2π 0 threshold, a lower energy than previously measured.

All measurements produced for this thesis have been sent to partial wave analysis groups where they will be used to provide constraints to their models. In particular, the 2π 0 measurements are expected to have an impact on our understanding of the poorly constrained properties of the N(1440) resonance, such as the branching ratios of its decay through intermediate meson or ∆ pathways.

The sPlot technique has been used for the first time in photoproduction experiments with advantages over other techniques discussed. The development of the technique for such analysis as this will be key for the extraction of many observables from future measurements.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Pion, photoproduction, hadron physics, MAMI, Mainz, A2.
• Subjects: Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Funder's Name: Science & Technologies Facilities Council (STFC)
• Supervisor's Name: Macgregor, Professor Douglas
• Date of Award: 2016
• Depositing User: Dr Simon S Gardner
• Unique ID: glathesis:2016-8024
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 20 Mar 2017 09:36
• Last Modified: 27 Apr 2017 07:23
• URI: https://theses.gla.ac.uk/id/eprint/8024