What Can We Learn from GPDs about the Structure of Protons?

[humanino]

I hear about a process called DVCS ("Deeply Virtual Compton Scattering") which should allow access to new distributions of parton called "generalized" distributions. Does someone know what's new about those "GPD" ?
DVCS at JLab Hall-A

 

[humanino]

OK, I see nobody really cares about quarks phenomenology. So I'm going to answer to myself. I am squatting your forum. (^_^)

I read that GPD would actually allow one to compute the T_\mu\nu of the partons ! (Energy-Momentum tensor) From a "naive" point of view, the only other way I can imagine to measure T_\mu\nu for the partons would be graviton scattering ! Therefore, my question was precisely : what physical quantity can be accessed through GPD (besides T_\mu\nu of partons) and what else remain to be measured inside a nucleon (or generally speaking a hadron), apart from what can be accessed with GPD ?