Instantons, diquarks, and nonleptonic weak decays of hyperons

This work is devoted to the study of the nonperturbative contributions in nonleptonic hyperon decays. We show that the instanton-induced 't Hooft interaction can naturally explain the ΔI=1/2 rule, by generating quark-diquark clustering inside octet baryons. We compute P-wave and S-wave amplitudes in the instanton liquid model, and find good agreement with experiment. We propose a model-independent procedure to test on the lattice if the leading quark-quark attraction in the 0+ antitriplet channel responsible for diquark structures in hadrons is originated by the interaction generated by quasiclassical fields or if it is predominantly due to other perturbative and/or confining forces.