Hadronic structure on the light front. V. Diquarks, nucleons, and multiquark Fock components

This work is a continuation in our series of papers that addresses quark models of hadronic structure on the light front, motivated by the QCD vacuum structure and lattice results. In this paper we focus on the importance of diquark correlations, which we describe by a quasilocal four-fermion effective 't Hooft interaction induced by instantons. The same interaction is also shown to generate extra quark-antiquark pairs of the sea. Its higher order iteration can be included via pion mediation: both taken together yield a quantitative description of the observed flavor asymmetry of antiquarks sea. Finally we discuss the final step needed to bridge the gap between hadronic spectroscopy and parton observables, by forward DGLAP evolution toward the chiral upper scale of similar to 1 GeV2.

Automated summary

This paper is part of our series of papers on quark models of hadronic structure on the light front, motivated by the QCD vacuum structure and lattice results. The focus of this paper is on the importance of diquark correlations, which are described by a quasilocal four-fermion effective 't Hooft interaction induced by instantons. This same interaction is also shown to generate extra quark-antiquark pairs of the sea. The inclusion of higher order iteration through pion mediation, along with the quark-antiquark pairs, provide a quantitative description of the observed flavor asymmetry of antiquarks sea. Finally, the paper discusses the final step needed to bridge the gap between hadronic spectroscopy and parton observables, which is the forward DGLAP evolution towards the chiral upper scale of similar to 1 GeV2.