Factorization of Short- and Long-range Interactions in Charged Meson Production
Meson production data play an important role in our understanding of nucleon structure. The combination of reaction channels is sensitive to gluon and charge and flavor non-singlet quark densities and has the potential to provide detailed images of the QCD quark structure of the nucleon. Quark imaging requires a good understanding of the reaction mechanism, and in particular rigorous tests of factorization of long- and short-distance physics. The higher energies after the Jefferson Lab 12 GeV upgrade provide ideal conditions for such studies, which are an essential prerequisite for studies of valence quark distributions. An electron-ion collider would allow to extend these studies to detailed imaging of sea quarks and gluons.