3D tomography of hadrons with hadron and lepton beams

Form factors defined by matrix elements of quark and gluon energy-momentum tensors are called gravitational form factors. They used to be considered as purely academic quantities without any experimental measurement because the gravitational interactions are extremely small in comparison with strong, electromagnetic, and weak interactions. However, due to recent developments of the hadron-tomography field, it became possible to determine these form factors from spacelike generalized parton distributions (GPDs) and their s-t crossed ones, generalized distribution amplitudes (GDAs). The GDAs could be called timelike GPDs. The spacelike and timelike GPDs are investigated in charged-lepton-scattering processes and electron-positron collisions, typically, by deeply virtual Compton scattering and two-photon processes, respectively [1]. In addition, hadron-accelerator [2] and neutrino [3] facility measurements will become possible in the near future. In this talk, I explain these GPD projects.