  We calculate the Sivers distribution functions induced by the final-state
interaction due to one-gluon exchange in diquark models of nucleon structure,
treating the cases of scalar and axial-vector diquarks with both dipole and
Gaussian form factors. We use these distribution functions to calculate the
Sivers single-spin asymmetries for inclusive pion and kaon production in
deep-inelastic scattering. We compare our calculations with the results of
HERMES and COMPASS, finding good agreement for pi+ production at HERMES, and
qualitative agreement for pi0 and K+ production. Our predictions for pion and
kaon production at COMPASS could be probed with increased statistics. The
successful comparison of our calculations with the HERMES data constitutes
prima facie evidence that the quarks in the nucleon have some orbital angular
momentum in the infinite-momentum frame.
