Chromodynamic Lensing and $\perp$ Single Spin Asymmetries

Abstract

The physical interpretation of generalized parton distributions (in the limit $\xi =0$) as Fourier transforms of impact parameter dependent parton distributions is discussed. Particular emphasis is put on the role of the target polarization. For transversely polarized targets we expect a significant deviation from axial symmetry for the distribution in the transverse plane. We conjecture that this transverse distortion, in combination with the final state provides a natural explanation for the sign of the Sivers contribution to semi-inclusive single-spin asymmetries.

8 pages, invited talk given at workshop on `light-cone 2003: Hadrons and Beyond' (Durham, August 2003) and at `NAPP 2003' (Dubrovnik, Croatia, May 2003)