What did we learn about GPDs from hard exclusive electroproduction of mesons?

Understand

It is reported on an analysis of electroproduction of light mesons at small Bjorken-x within the handbag approach.

• The partonic subprocesses, meson electroproduction off quarks or gluons, are calculated within the modified perturbative approach in which quark transverse momenta are retained.
• The soft hadronic matrix elements, generalized parton distributions, are constructed by means of double distributions.
• The constraints from parton distributions and sum rules are taken into account.