The Role of Gauge Invariance in Single-Spin Asymmetries

Abstract

We argue that through the Wilson lines, gauge invariance has as an effect that the hard functions in weighted spin-asymmetries in hadronic scattering processes are given by gluonic pole cross sections, rather than the usual partonic cross sections.

Comments: Talk presented at the 15th International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2007), April 16-20, 2007, Munich, Germany