The Science and Status of the Electron Ion Collider

Despite decades of experimental and theoretical investigations many important questions in Quantum Chromodynamics (QCD), remain unanswered. We know since 1960s that protons and neutrons (nucleons) -- the building blocks of the visible universe -- are made up of quarks and gluons (partons). However, we do not yet understand exactly how the parton interactions constitute the nucleons and impart them properties such as their spin and mass. Questions also remain in the nuclear regime. For example, what is the quark-gluon nature of nuclear binding? How does a high energy parton interact with cold nuclear matter? How is a color-neutral object formed starting from the colored parton (hadronization)? Lastly, what happens to parton densities in hadrons and nuclei at high energy? QCD suggests emergence of a novel saturated gluonic state of matter often called the Color Glass Condensate. However, it cannot predict exactly what energy and parton density is needed to create it. These and such questions were summarized in the Electron Ion Collider (EIC) White Paper and a case for the EIC was made. The 2015 US nuclear science long range plan enthusiastically supported this. In 2018 the National Academy of Sciences, Engineering and Medicine (NAS) found these questions compelling and extremely important to understand the last remaining secrets of atomic nuclei. The US DOE has since moved to realize the high-luminosity, high-energy EIC with polarized beams as proposed in the White Paper. The EIC is being built at Brookhaven National Laboratory (BNL) jointly by BNL and Jefferson Laboratory (JLab) with enthusiastic international community participating both in the accelerator and detector design and development. In this talk I will summarize the scientific motivation for the EIC and the status of the project.