The science and prospects of the future electron ion collider

While no one doubts that Quantum Chromodynamics (QCD) is the correct theory of Strong Interactions, our understanding of it remains far from complete. Intellectually compelling questions of high significance remain unanswered. How does the gluon distribution look in hadron and nuclei at extremely high energy? Do the gluons saturate forming a new saturated state of matter as predicted by some non-linear extensions of perturbative QCD? What role do the partons, and in particular, gluons play in imparting the properties of a proton such as mass and spin? Do the partons move transversely inside the nucleon and contribute dynamically to the proton spin