Two-body densities as a framework for dynamical imaging and their connection to ultra-peripheral collisions

Abstract

We present results on two-parton densities in coordinate space which capture a fuller dynamical picture of the proton’s internal structure, including information on the relative position between quarks and gluons in the transverse plane. The connection of such two-body densities to observables, proceeds in QCD, via the definition of  double generalized parton distributions (DGPDs) that can be accessed in the production of two vector mesons, or two dimuon systems in ultraperipheral collisions (UPCs) through a double scattering process.