Deeply virtual Compton scattering off Helium nuclei with positron beams · arXivDesk
2105.00435May 2, 20218 pages, 8 figures, invited article for the EPJA Topical Issue about "Positron beams and physics at Jefferson Lab". arXiv admin note: substantial text overlap with arXiv:2007.15081
Deeply virtual Compton scattering off Helium nuclei with positron beams
Sara Fucini, Mohammad Hattawy, Matteo Rinaldi, Sergio Scopetta
Positron initiated deeply virtual Compton scattering (DVCS) off 4He and 3He nuclei is described. The way the so-called d−term could be obtained from the real part of the relevant Compton form factor is summarized, and the importance and novelty of this measurement is discussed. The measurements addressed for 3
Nearby in the stack
He targets could be very useful even in a standard unpolarized target setup, measuring beam spin and beam charge asymmetries only. The unpolarized beam charge asymmetries for DVCS off
3
He and
4
He are also estimated, at JLab kinematics and, for
4
He, also at a configuration typical at the future Electron-Ion Collider. Incoherent DVCS processes, in particular the ones with tagging the internal target by measuring slow recoiling nuclei, and the unique possibility offered by positron beams for the investigation of Compton form factors of higher twist, are also briefly addressed.