The discontinuities in twist-3 GPDs

We find in one-loop calculations and spectator models that twist-3 GPDs exhibit discontinuities. In the forward limit these discontinuities grow into Dirac delta functions. Neglecting these Dirac delta functions leads to an apparent violation of sum rules for twist-3 PDFs. We calculate quasi-PDFs and identify the Dirac delta function terms with momentum components in the nucleon state that do not scale as the nucleon is boosted to the infinite momentum frame.