Parton Distributions in Light-Cone Gauge: Where Are the Final-State   Interactions?
  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. 
Xiangdong Ji and Feng Yuan