Speaker: Stephan Meissner (Ruhr U., Bochum)

Title: New results on relations between GPDs and TMDs from the analysis
of GTMDs

Abstract:
Parton distributions are an essential tool for the QCD description of
hadronic scattering processes. In particular, generalized parton
distributions (GPDs) and transverse momentum dependent parton
distributions (TMDs), which appear in connection with hard exclusive and
semi-inclusive reactions, respectively, attracted a lot of interest
during the last decade. Although GPDs and TMDs are a priori two distinct
objects, model calculations reveal possible nontrivial relations between
them. From the phenomenological point of view, such relations are very
promising, as they provide, e.g., an intuitive picture of the Sivers
effect. However, further studies indicate that the nontrivial relations
between GPDs and TMDs may not hold in general. In this talk, this will
be demonstrated explicitly by analyzing so-called generalized transverse
momentum dependent parton distributions (GTMDs), which parameterize the
most general quark-quark correlator of the nucleon and contain the GPDs
and TMDs in certain limits.