OPE-based Methods in Nonperturbative QCD

Abstract

I describe the inception and development of nonperturbative OPE-based methods in hadronic physics, such as the SVZ sum rules, inverse heavy quark mass expansion (IHQME) and so on and related topics.

Comments: 11 pages, 4 figures; V2 a reference to a fresh publication added (with a brief comment), typos corrected. Invited contribution to the EPJC Volume celebrating 50 years of Quantum Chromodynamics, to be published in December 2022 [arXiv:2212.11107]