Contribution invited talk
DVCS and exclusive neutral pion at Jefferson Lab: Accomplishments and future developments
Generalized Parton Distributions (GPDs) have become a major topic in the field of hadronic physics and nucleon structure. They parameterize the momentum of the quarks and gluons momentum in correlation with their spatial distribution inside the nucleon, which provides a three-dimensional picture of the nucleon. This feature makes GPDs a powerful tool to study the orbital momentum of partons inside the nucleon, which is the missing piece of the nucleon spin puzzle.
GPDs are studied with the measurements of exclusive leptoproduction channels such as Deeply Virtual Compton Scattering (DVCS) $\ell N \rightarrow \ell N \gamma$, and exclusive meson production $\ell N \rightarrow \ell N h$ ($h=\pi, \rho, \omega, ...$), in the deep inelastic scattering regime. DVCS is usually the most favored (``golden'') channel to study GPDs, and is always associated with exclusive $\pi^0$ production measurements (as both require identical experimental setups), which is also highly relevant for flavor separation.
Jefferson Laboratory, with its high intensity polarized electron beam accelerator has been dedicating a significant share of its research resources to a variety of DVCS/$\pi^0$ measurements in its different experimental halls. The interest for the GPD related measurements at Jefferson Lab has been further enhanced with the recent Jefferson Lab beam energy upgrade from 6 to 12 GeV.
After a brief introduction on the GPDs phenomenology, I will develop on the DVCS/$\pi^0$ production measurements achieved at Jefferson Lab 6 GeV, highlighting how these data has improved our understanding on the nucleon structure. I will also point out the many questions those data have raised, and how we are planning to address these through the different measurements programmed at Jefferson Lab for the 12 GeV era.