Generic framework for non-perturbative QCD in light hadrons

Abstract

This paper aims to serve as an introductory resource for disseminating the concept of instanton liquid model to individuals with interests in quantum chromodynamics (QCD) for hadrons. We discuss several topological aspects of the QCD vacuum and briefly review recent progress on this intuitive unifying framework for the lowlying hadron physics rooted in QCD by introducing the vacuum as a liquid of pseudoparticles. We develop systematic density expansion on the dilute vacuum with diagrammatical Feynman rules to calculate the vacuum expectation values (VEVs) and generalize the calculations to hadronic matrix element (charges), and hadronic form factors using the instanton liquid model (ILM). The ILM prediction are well-consistent with those of recent lattice QCD calculations. Thereby, the nonperturbative physics can be well-controlled by only a few parameters: instanton size $\rho$ and instanton density $n_{I+A}$, and current quark mass $m$.