Covariant diquark-quark model of the nucleon in the Salpeter approach.

We develop a rather simple, formally covariant quark-diquark model of the nucleon. The nucleon is treated as a bound state of a constituent quark and a diquark interacting via a quark exchange. We include both scalar and axial-vector diquarks. The underlying Bethe-Salpeter equation is transformed into a pair of coupled Salpeter equations. The electromagnetic form factors of the nucleon are calculated in the Mandelstam formalism. We obtain a very good description of all electromagnetic form factors for momentum transfers up to −3 (GeV/c)2. PACS numbers: 13.40.Gp, 13.39.Ki, 14.20.Dh, 11.10.St e-mail: [email protected] Tel.: +49 (0)228 73 2377 Fax: +49 (0)228 73 3728