Speaker
Description
Generalized Parton Distributions (GPDs) describe the correlations between the longitudinal momentum and the transverse position of the partons inside the nucleon. They are nowadays the subject of an intense effort of research, in the perspective of understanding nucleon spin and the nucleon Gravitational Form Factors (GFFs). Experimentally and theoretically, the most studied reaction to access GPDs is Deeply Virtual Compton Scattering (DVCS). In this talk, we present complementary ways to access GPDs using dilepton photo- and electro-production with the CLAS12 detector. First, we present the first measurement of the beam polarization asymmetry and angular asymmetry of the Timelike Compton Scattering reaction (the hard photoproduction of a lepton pair) using data taken in the Fall of 2018 by CLAS12. We then highlight the current effort to extract the near-threshold J/ψ photoproduction cross section from CLAS12 data. This measurement is expected to provide direct insight on the gluons GPDs of the proton. Finally, we expose the potential of CLAS12 to measure the Double Deeply Virtual Compton Scattering reaction (the electro-production of a pair of leptons). This measurement, allowing to probe the full kinematic dependence of the GPDs, would be possible with a future luminosity upgrade of CLAS12, including the installation of a dedicated muon detector.
