Speaker
Pawel Sznajder
(National Centre for Nuclear Research)
Description
We discuss the problem of model dependency in the extraction of generalized parton distributions (GPDs). In processes like deeply virtual Compton scattering (DVCS), this problem is highlighted by the presence of 'shadow' GPDs, which do not contribute to observables for this process. The problem can be solved by considering double deeply virtual Compton scattering (DDVCS), which will be discussed in this talk. The other solution may come thanks to the recent breakthrough in evaluating GPDs from lattice QCD. Inclusion of lattice QCD results in GPD phenomenology requires, however, flexible modeling, which will be briefly mentioned as well.
