Conveners
PWG - 3: TBD
- Jan Bernauer (Stony Brook University / RBRC)
One of the principal motivations for accelerating positrons in CEBAF is to perform direct measurements of positron-proton elastic scattering observables, toward a conclusive resolution of the long-standing discrepancy between extractions of the proton electromagnetic form factor ratio based on cross section measurements and double-polarization observables, especially polarization transfer....
In this talk I will discuss beam and target normal single-spin asymmetries in electron--proton elastic scattering. Our calculation of the imaginary part of two-photon exchange amplitudes considers resonance intermediate states of spin-parity 1/2± and 3/2± and mass W<1.8 GeV. The latest CLAS exclusive meson electroproduction data are used as input for the transition amplitudes from the proton...
Two-photon exchange gives rise to distinctive spin effects in electron/positron-nucleon scattering, which can be observed in inclusive or exclusive (elastic/inelastic) measurements. We report about recent progress in computing the transverse target single-spin asymmetry in ep scattering the resonance region, using systematic methods based on the 1/Nc expansion of QCD [1, 2]. We discuss the...
The connection of experimental data, notably in the DVCS channel, to generalized parton distributions (GPDs) faces a notoriously difficult deconvolution problem. I will present an impact study of the plausible impact of the positron beam on the extraction of Compton form factors, and discuss how this is a very useful data to consolidate the extraction of GPDs.
For the past 25 years, many JLab experiments have been dedicated to determining the Generalized Parton Distributions (GPDs), especially by measuring Deeply Virtual Compton Scattering (DVCS) observables. The GPDs describe the correlation between longitudinal momentum fraction and transverse position of partons in the nucleons. GPDs also give access to the Gravitational Form Factors (GFFs)...
We discuss opportunities with positron beams for the study of parton distribution functions of the nucleon in deep-inelastic scattering and related processes. Specific topics include the flavor separation of the unpolarized PDFs as well as the spin-dependent distributions.
