Date Thesis Awarded


Access Type

Honors Thesis -- Open Access

Degree Name

Bachelors of Science (BS)




Justin Stevens

Committee Members

Irina Novikova

Heather Sasinowska


The structure of protons is a point of interest in nuclear physics due to the lack of consensus between the cumulative spin of a proton and the sum of the spins of its constituent quarks. In the GlueX Experiment at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF), a particle physics process known as Timelike Compton Scattering (TCS), given by the reaction 𝛾𝑝 β†’ 𝑝𝑒+𝑒-, can be used to help potentially explain this discrepancy. With an eventual goal of providing a comparison of the experimental GlueX TCS data to Generalized Parton Distribution (GPD) models, initial research focused on isolating a pure TCS signal from a larger data set containing primarily the background reaction 𝛾𝑝 β†’ π‘πœ‹+πœ‹-. After identifying and placing range restrictions upon experimental variables which are sensitive to the differences between 𝑒± and πœ‹Β± data, next steps included identifying the scattering plane angles of the electrons and positrons; significant variables in the cross section ratio present in GPDs. Our resulting plot of the πœ™ plane vs detected 𝑒+𝑒- events indicated that the application of the restrictions that I selected and implemented to a larger data set will make it possible to more conclusively determine the presence and receptivity of TCS to GPD parameters.