Deeply Virtual Compton Scattering with Positron Beams at Jefferson Lab

Abstract

A brief discussion of the DVCS program at the Jefferson Lab 12 GeV energy upgrade is given. Emphasis is on what can be learned from using both polarized electron and polarized positron beams in conjunction with polarized nucleon targets.Comment: 6 pages, 4 figures, invited talk at the Workshop on Positron beams JLab, Newport News, March, 200

Beam charge asymmetries for deeply virtual Compton scattering off the proton

“…10 for the full set of kinematics accessible with CLAS12, using the 2 CFF parameterizations. The left panel shows the model e[H] as a function of −t for different (x B , Q 2 ) bins (line), together with the extracted values with- U U data for selected bins [34]; blue points correspond to projected data smeared according to their statistical error; red lines are the model prediction used to generate experimental observables. LU data for selected bins [34]; blue points correspond to projected data smeared according to their statistical error; red lines are the model prediction used to generate experimental observables.…”

“…Fig.5Kinematic coverage of exclusive DVCS/BH events in Q 2 versus x B (top), and in -t versus the azimuthal φ-dependence (bottom), from a subset of electron beam data[34].…”

“…Fig.8Out-of-plane φ-distribution of a subset of projected A C U U data for selected bins[34]; blue points correspond to projected data smeared according to their statistical error; red lines are the model prediction used to generate experimental observables.…”

Double deeply virtual Compton scattering with positron beams at SoLID

“…Experimentally, Beam Charge Asymmetries (BCAs) are more difficult observables to obtain than BSAs since some detector related effects (efficiency, solid angle) may still persist when comparing electron and positron data [22]. The theoretical BCAs can be constructed as…”

Topical issue on an experimental program with positron beams at Jefferson Lab

“…The physics potential of a positron beam experimental program at JLab was first presented to the Program Advisory Committee (PAC46) in the form of a letter of intent [5]. Two years later, the JLab PWG released the Positron White Paper [6] at the same time that two proposals were presented at the PAC48 [7,8], followed by a third one the year after at the PAC49 [9]. The present Topical Issue is an extented and elaborated version of the Positron White Paper.…”