Is There Diquark Clustering in the Nucleon?

We show how the instanton-induced interaction in qq pairs, iterated in tchannel, leads to a meson-exchange interactions between quarks. Thus one can achieve a simultaneous understanding of low-lying mesons, baryons and the nuclear force. Our discussion is rather general in this respect and does not rely necessarily on the instanton-induced interaction. Any nonperturbative gluonic interaction between quarks, which is a source of the dynamical chiral symmetry breaking and which thus explains π ρ mass splitting, will imply an effective meson exchange picture in baryons. Because of (anti)screening a big difference appears between the initial ’t Hooft interaction and the effective meson-exchange interaction. We demonstrate that the effective mesonexchange interaction, adjusted to baryon spectroscopy, does not bind a scalar diquark and does not induce an appreciable quark-diquark clustering in the nucleon because of a nontrivial role played by the Pauli principle.