Pole term and gauge invariance in deep inelastic scattering

In this paper we reconcile two contradictory statements about deep inelastic scattering in manifestly covariant theories: (i) the scattering must be gauge invariant, even in the deep inelastic limit, and (ii) the pole term (which is not gauge invariant in a covariant theory) dominates the scattering amplitude in the deep inelastic limit. An open-quotes intermediateclose quotes answer is found to be true. We show that, at all energies, the gauge-dependent part of the pole term cancels the gauge-dependent part of the rescattering term, so that both the pole and rescattering terms can be redefined separately in a gauge-invariant fashion. The resulting, redefined pole term is then shown to dominate the scattering in the deep inelastic limit. Details are worked out for a simple example in 1+1 dimensions. copyright 1998 The American Physical Society