Beam-spin asymmetry of deeply virtual Compton scattering off the proton at 10.6 GeVwith CLAS12 at Jefferson Laboratory

Christiaens, Guillaume (2021) Beam-spin asymmetry of deeply virtual Compton scattering off the proton at 10.6 GeVwith CLAS12 at Jefferson Laboratory. PhD thesis, University of Glasgow.

Abstract

This thesis presents the measurements of beam-spin asymmetry (BSA) of deeply virtual Compton scattering (DVCS) off the proton at 10.6 GeV with the CLAS12 spectrometer at Jefferson Laboratory. This data will provide, in the valence region, high energy DVCS measurements, to help constrain nucleon structure physics models.

The data used in this thesis was taken at Jefferson Laboratory (Virginia, USA). The CLAS12 spectrometer, installed in the experimental hall B, receives a longitudinally polarized electron beam accelerated to up to 10.6 GeV. CLAS12 provides the identification and reconstruction of the particles obtained from the interaction of the electron beam with a fixed liquid hydrogen target.

Micromegas detectors were used to improve the tracking resolution within the CLAS12 spectrometer. This thesis provides a description of the assembly, integration and operation of Micromegas detectors. The integration of the Micromegas detectors with the other CLAS12 sub-systems, the integration of the gas and software systems as well as tests and studies performed during the commissioning are detailed.

In this thesis, the DVCS process was extracted from the data collected by CLAS12 and the BSA was computed. The emphasis was put on the exclusive selection of DVCS signal and the estimation of the π0 electroproduction background. The DVCS exclusivity variables and the positions of the exclusivity cuts were optimised to reduce the π0 electroproduction background and the remaining contamination was estimated from a Monte-Carlo simulation. The BSA was extracted for 240 kinematic bins with: ten φ bins, four t bins, three xB bins and two Q2 bins.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: I acknowledge CEA Saclay and the University of Glasgow for funding this research.
• Subjects: Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Sokhan, Dr. Daria, Ireland, Prof. David and Defurne, Maxime
• Date of Award: 2021
• Depositing User: Theses Team
• Unique ID: glathesis:2021-82288
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 25 Jun 2021 15:21
• Last Modified: 19 Aug 2022 15:58
• Thesis DOI: 10.5525/gla.thesis.82288
• URI: https://theses.gla.ac.uk/id/eprint/82288