Calendar of Events

COL - The Electron-Ion Collider - peering deeper into the protons and neutrons of atomic nuclei

Ernst Sichtermann, Lawrence Berkeley Laboratory

The proton, along with its uncharged partner, the neutron, is at the core of every atom. Collectively, protons and neutrons are known as nucleons. They make up the vast majority of visible matter in the universe. Experimental and theoretical investigations over the past half a century have revealed that nucleons have rich inner structures with strongly interacting quarks and gluons, and have yielded a number of surprises. Only about a percent of the nucleon's mass stems from the rest mass of the quarks, and the remainder thus stems from the zero-point energy of the quarks, anti-quarks, and gluons. The gluon, in particular, has proven elusive and open questions include their spatial distribution, their role for nucleon spin, and emergent phenomena from gluon self-interaction. To address these questions, the U.S. Nuclear Physics Community has proposed to construct a forefront accelerator facility, the Electron-Ion Collider (EIC). The EIC will have unique capabilities to collide beams of polarized electrons with beams of polarized protons, polarized light ions, or heavier ions over a range of collision energies and with high luminosity. I will discuss the context, science, and status of the EIC.