Parton Distributions in Light-Cone Gauge: Where Are the Final-State Interactions?

Abstract

We show that the final-state interaction effects in the single target spin asymmetry discovered by Brodsky et al. can be reproduced by either a standard light-cone gauge definition of the parton distributions with a prescription of the light-cone singularities consistent with the light-cone gauge link, or a modified light-cone gauge definition with a gauge link involving the gauge potential at the spatial infinity.

Figures (3)

• Figure 1: One-loop contribution to the spin-dependent transverse momentum distribution in the nucleon.
• Figure 2: Tree contribution to the spin-independent transverse momentum distribution.
• Figure 3: a). Extra contributions from the light-cone gauge parton distribution compared to the Feynman gauge distribution without the light-cone link. b) The light-cone-link contributions to the Feynman gauge distribution.