Speaker
Joerg Pretz
(Universitaet Bonn)
Description
In the Quark Parton Model, the nucleon is successfully described in terms of parton distribution functions (PDFs). Whereas unpolarized parton distributions like $q(x)$ and $g(x)$ interpreted as number densities of quarks and gluons at a given longitudinal momentum fraction $x$ in the nucleon are relatively well known, distribution involving polarization degrees of freedom are less well known.
The most prominent ones, related to the nucleon spin problem, are the helicity distributions $\Delta q(x)$, $\Delta G(x)$ and the transversity distributions $\Delta q_T(x)$. The picture of the Quark Parton Model can be extended if in addition transverse momenta or the transverse position of partons inside the nucleon are considered. This leads to the introduction of transverse momentum distributions (TMDs) and generalized parton distributions (GPDs), respectively.
An overview of recent experimental results and future plans will be given.
Primary author
Joerg Pretz
(Universitaet Bonn)
