Inclusive Single-Spin Asymmetries, Quark-Photon, and Quark-Quark   Correlations
  We consider quark-photon correlations that have been proposed as a source for single-spin asymmetries in inclusive deep-inelastic scattering. A new sum rule for these correlators is derived and its phenomenological consequences are discussed. The results are interpreted within the context of an intuitive 'electrodynamic lensing' picture. 
Matthias Burkardt
hep-ph