Spin Physics: Session Summary

Abstract

Many spin physics experiments have been performed in recent years and many new exciting results have been reported at DIS 2007 [1], which will be highlighted in this summary. Also on the theory side many new results were reported, especially regarding transverse spin effects which are most challenging. Recent years have seen quite some unexpected developments concerning so-called TMDs, transverse momentum dependent parton distributions, and we can look forward to more such developments over the coming years. Therefore, this summary is very much a snapshot of the current status. This summary is split into three main parts. We start with longitudinal spin physics, most notably, experimental results on gluon polarization. We proceed with transverse spin, which is mainly focused on transverse spin asymmetries and the possible explanation in terms of TMDs. The third and last part is about exclusive processes and generalized parton distributions, which provide more detailed information about the spatial distribution of partons inside hadrons. This spatial distribution is often probed using spin asymmetries and recent developments have started to point to a connection between GPDs and TMDs. A very interesting development.