Measurement of deeply virtual Compton scattering off He4 with the CEBAF Large Acceptance Spectrometer at Jefferson Lab

We report on the measurement of beam spin asymmetry in deeply virtual Compton scattering off He4 using CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab a 6 GeV longitudinally polarized electron incident pressurized gaseous target. detail method used to ensure exclusivity measured reactions, particular upgrade CLAS with radial time projection chamber detect low-energy recoiling nuclei and an inner calorimeter extend photon detection acceptance forward angles. Our results confirm theoretically predicted enhancement coherent (eHe4→e′He4′γ′) asymmetries compared those observed free proton, while incoherent (eHe4→e′p′γ′X′) exhibit 30% suppression. From data, we were able extract, model-independent way, real imaginary parts only form factor, HA, leading way toward 3D imaging partonic structure nuclei.16 MoreReceived 19 February 2021Accepted July 2021DOI:https://doi.org/10.1103/PhysRevC.104.025203©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasForm factorsLepton induced nuclear reactionsPerturbative QCDQCD reactionsNuclear PhysicsParticles & Fields