Studying diquark correlations in the nucleon by means of lattice QCD simulations

In this presentation we review our recent attempt to address two questions concerning dynamical correlations inside the nucleon: (i) is the non-perturbative quark-quark interaction particularly attractive in the color antitriplet 0+ diquark channel? (ii) are such correlations induced by instantons? We define appropriate ratios of Euclidean three-point functions which encode specific information about two-body correlations and can be computed on the lattice. We analyze such correlations functions in different models with very different diquark content: a naive non-relativistic SU(6) quark model, the Random Instanton Liquid Model and the Quark Chiral Soliton Model. We show that such models lead to radically different predictions. We conclude that a lattice QCD calculation of such correlation functions can determine which picture is most realistic.