QCD Instanton Effects in High Energy Processes

摘要

The nonperturbative effects in the processes involving strongly interacting particles are systematically studied within the instanton liquid model (ILM) of the QCD vacuum. A detailed analysis of the nonperturbative contributions to the electomagnetic quark form factor is presented. We consider the structure of the instanton-induced effects in the evolution equation describing the high energy behavior of the form factor and demonstrate that the instanton contributions result in the finite renormalization of the subleading perturbative result and numerically are characterized by a small factor reflecting the diluteness of the QCD vacuum. The consequences of the IR renormalon-induced effects, as well as various analytization procedures of the strong coupling constant in the IR domain, are considered. The role of the instanton-induced effects in high energy diffractive quark–quark scattering, in particular, in the formation of the soft Pomeron, is discussed. The further applications of the approach developed to the study of the nonperturbative effects in high energy hadronic processes are discussed.