Seminarium Fizyki Wielkich Energii

Generalised Parton Distrbutions (GPDs) provide 3-D description of the nucleon structure. They encompass 1-D description by PDFs or by form factors. The two most appealing goals of the GPD studies are: the „nucleon tomography” and the role of the orbital momenta of quarks and gluons in explaining „nucleon spin crisis”. After an introduction to the GPDs, the upgrade of the experimental setup, which was essential for the COMPASS GPD program, will be briefly described. The discussion of results for investigated three channels of exclusive pseudo-scalar or vector mesons production will follow.They consitute an important input for modelling GPDs. In particular, in the context of the phenomenological Goloskokov-Kroll model they provide a clear evidence for the parton helicity-flip (chiral-odd) GPDs.