Exposing Novel Quark and Gluon Effects in Nuclei
Understanding the emergence of nuclei within QCD is a key challenge for modern science, yet in the 40-plus years since the advent of QCD clear evidence for novel quark and gluon effects in nuclei has been lacking. Nuclear physics approaches where the Hamiltonian is comprised of hadronic states have had significant success in describing the properties of nuclei across the chart of nuclides, with this success likely connected with color confinement in QCD. However, because QCD is the fundamental theory of the strong interaction, it is unlikely that these hadron-level approaches can remain valid, or contain the correct degrees of freedom, for all processes at all energy scales. Clearly identifying these scales and processes is key to exposing the role of quarks and gluons in nuclei and thereby developing an understanding of how nuclei emerge within QCD. This workshop will explore these ideas by bringing together nuclear physicists from both the hadronic and QCD degrees of freedom perspectives. Discussions will review the best evidence we currently have for novel quark and gluon effects in nuclei, such as the EMC effect and the possible quenching of the Coulomb sum rule, and then explore what may be learned through processes such as parityviolating, spin-dependent, and tagged DIS; neutrino and nucleon knock-out reactions; and ultimately developing a quark and gluon tomography of nuclei which is provided by their GPDs and TMDs. Such discussions are important for the Jefferson Lab and relativistic heavy-ion programs, the QCD programs at FAIR and Fermilab, neutrino experiments, and the design of a future electron-ion collider.
