Impact Parameter Dependent Parton Distributions and Off-Forward Parton   Distributions for $\zeta\to 0$
  It is shown that off-forward parton distributions for $\zeta =0$, i.e. where the initial and final state differ only in their transverse momenta, can be interpreted as a simultaneous measurement of the longitudinal momentum and transverse position (impact parameter) of partons in the infinite momentum frame. 
Matthias Burkardt (New Mexico State University)