Deeply Virtual Compton Scattering Beam-Spin Asymmetry at 6.5 GeV and 7.5 GeV Polarized Electron Beam with CLAS12

Deeply Virtual Compton Scattering (DVCS) is the cleanest channel providing access to the 3D nucleon imaging mapped by Generalized Parton Distributions (GPDs) which correlate the 1D longitudinal momentum fraction of the nucleon’s constituent to its 2D transverse position. In DVCS reaction, the virtual photon from the scattered electron interacts with a quark inside the nucleon, leading to the emission of a high-energy real photon from the nucleon. Detection of DVCS events, however, implies detection of Bethe-Heitler (BH) events, which have the same final-state particles but with the scattered electrons emitting the photons. DVCS measurements at different beam energies allow DVCS amplitude and DVCS-BH interference amplitude’s separation necessary for the extractions of GPD H in some kinematics, and eventually the gravitational  form factor, which encodes the mechanical properties of the nucleon.

The combination of highly luminous and highly polarized electron beam and Hall B’s large-acceptance CLAS12 detector system at Jefferson Lab offers the ideal setup for multi-energy DVCS experiments in broad kinematic ranges.

DVCS data were collected with CLAS12 in 2018 at 6.5 GeV, 7.5 GeV, and 10.6 GeV electron beam energies on liquid hydrogen target. We will present preliminary DVCS measurements at 6.5 GeV and 7.5 GeV beam energies from the recent analysis of Beam-Spin Asymmetry, which is particularly sensitive to the  GPD and is an essential ingredient in the extraction of the  form factor.