Nucleon form factors and a nonpointlike diquark

Nucleon form factors are calculated on q{sup 2}(set-membership sign)[0,3] GeV{sup 2} using an ansatz for the nucleon's Faddeev amplitude motivated by quark-diquark solutions of the relativistic Faddeev equation. Only the scalar diquark is retained, and it and the quark are confined. A good description of the data requires a nonpointlike diquark correlation with an electromagnetic radius of 0.8 r{sub {pi}}. The composite, nonpointlike nature of the diquark is crucial. It provides for diquark-breakup terms that are of greater importance than the diquark photon absorption contribution. (c) 1999 The American Physical Society.