Abstract：

The nucleons (protons and neutrons) are responsible for more than 99% of the mass of the visible matter in the universe. Contrary to the conventional wisdom, Higgs Mechanism is not the main mechanism responsible for the nucleon mass. How the global properties of the nucleon, such as mass and spin, come from its internal structure and how they can be experimentally studied are the focus of this talk. The internal structure of the nucleon is mostly governed by the strong interaction. Although a successful theory (QCD) to describe the strong interaction was established 40 years ago, our understanding of the strong interaction in its truly strong region is still very limited. Understanding nucleon’s 3-d internal structure and the strong interaction in the strong region is the new frontier of the modern high-energy nuclear physics. Electron scattering and electron-ion colliding have been the most powerful and precise tools in this study. An overview of the progress and selected highlights will be presented. Physics programs at Jefferson Lab and at possible future electron-ion colliders will be discussed.