Measurement of the Deeply Virtual Compton Scattering Cross Section from the Proton at 10.6 GeV using the CLAS12 Detector

Deeply Virtual Compton Scattering (DVCS) is an exclusive process that produces a real photon when a lepton scatters from a quark inside a nucleon or a nucleus. Measurement of the DVCS cross section enables the study of the Generalized Parton Distributions (GPD), which plays a central role in underst...

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Bibliographic Details
Main Author: Lee, Sangbaek
Other Authors: Milner, Richard G.
Format: Thesis
Published: Massachusetts Institute of Technology 2023
Online Access:https://hdl.handle.net/1721.1/150759
https://orcid.org/0000-0001-6038-0736
Description
Summary:Deeply Virtual Compton Scattering (DVCS) is an exclusive process that produces a real photon when a lepton scatters from a quark inside a nucleon or a nucleus. Measurement of the DVCS cross section enables the study of the Generalized Parton Distributions (GPD), which plays a central role in understanding the QCD dynamics inside a hadron. Thus, the quark and gluon origin of the nucleon spin and mass can be probed and three-dimensional images of the target nucleon or nucleus can be realized. This thesis presents a cross section analysis of DVCS from the proton in the presence of its background, Bethe-Heitler (BH) process. The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam en-ergy (CLAS12) collaboration has taken electron-proton scattering data in fall 2018 using a liquid hydrogen target and the 10.6 GeV polarized electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF). The CLAS12 detector is a nearly hermetic fixed-target detector, located in Hall B, Jefferson Lab at Newport News, Virginia. The experimentally determined BH-DVCS cross section is in good agreement with a phenomenological-model based theoretical prediction. The kinematic dependence of the cross section is reported over a wide range. The short-term plan to utilize the results presented here for a thorough tomography study and the long-term plan for GPD studies at future facilities such as the Electron-Ion Collider (EIC) are discussed.