Positrons at JLab - Advancing Nuclear Science in Hall B

Abstract

In this talk I address two high impact physics programs that require the use of polarized and unpolarized positron beams in addition to using electron beams of the same energy. First, I address what will be gained from using positron beams in addition to electron beams in the extraction of the Compton Form Factors (CFFs) and generalized parton distributions (GPDs) from Deeply Virtual Compton Scattering (DVCS) on a proton target. As a second high impact science program I discuss an experimental scenario using unpolarized positrons to measure elastic scattering on protons in an effort to determine definitively the 2-photon exchange contributions in order to resolve a longstanding discrepancy in the determination of the proton's electric and magnetic form factors.

9 pages, 9 figures

References in corpus (8)

• Measurement of the two-photon exchange contribution to the elastic $e^{\pm }p$ scattering cross sections at the VEPP-3 storage ring
• Two-photon exchange in elastic electron-proton scattering
• Towards a resolution of the proton form factor problem: new electron and positron scattering data
• Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment
• Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target
• Longitudinal target-spin asymmetries for deeply virtual Compton scattering
• The dual parameterization of the proton generalized parton distribution functions H and E and description of the DVCS cross sections and asymmetries
• On the mistake in the implementation of the minimal model of the dual parameterization and resulting inability to describe the high-energy DVCS data