An Electron-Ion Collider may provide an exceptionally fertile environment to study the dynamics of nuclei at short distances. A key goal is to understand the quark and gluon substructure of nucleons and nuclei, their role in nuclear binding and in general, in short-range nuclear correlations. Since the discovery of the EMC effect, these studies have yielded many surprises and continuing puzzles, an example of which are the strong short-range nucleon-nucleon correlations discovered at Jlab. Results from RHIC and LHC on multiparticle correlations in light-heavy ion collisions indicate a larger than anticipated role of quark and gluon spatial correlations. An important question is how these studies can impact our understanding of nuclear structure and correlations across energy scales.
The EIC brings new elements to these studies. The higher energies allow access to the gluon dominated regime in nucleons and nuclei; these, combined with high luminosities, permit highly differential studies of exclusive and diffractive final states. Beams of polarized light nuclei will permit extraction of the spin dependence of short-range forces. Not least, because the fragmentation of struck nuclei can be widely separated spatially from the fragmentation region of the lepton current, the EIC can in principle cleanly probe the distribution of nuclear fragments. Such measurements pose significant challenges to the design of the detector and the interaction region at the EIC.
A first one-day workshop exploring some of the ideas outlined was held in March 2017 at Catholic University of America in Washington DC. Because of the interest generated by this workshop, and on-going theoretical and experimental developments, it is timely to explore in greater depth the potential of EIC to reveal the underlying structure of short-range nuclear correlations in terms of the underlying quark and gluon fields of QCD. The workshop will bring together interested scientists from a diverse range of sub-fields of nuclear physics to discuss their perspectives on these issues. We envisage a program of a few overview presentations on key questions and puzzles, along with shorter focused presentations, and plenty of time reserved for discussions.
J. H. Le