Three Lectures on Hadron Physics

TL;DR: In this paper, the authors compare experiment and theory to expose the impact of running couplings and masses on hadron observables and thereby aid materially in charting the momentum dependence of the interaction that underlies strong-interaction dynamics.

Abstract: These lectures explain that comparisons between experiment and theory can expose the impact of running couplings and masses on hadron observables and thereby aid materially in charting the momentum dependence of the interaction that underlies strong-interaction dynamics. The series begins with a primer on continuum QCD, which introduces some of the basic ideas necessary in order to understand the use of Schwinger functions as a nonperturbative tool in hadron physics. It continues with a discussion of confinement and dynamical symmetry breaking (DCSB) in the Standard Model, and the impact of these phenomena on our understanding of condensates, the parton structure of hadrons, and the pion electromagnetic form factor. The final lecture treats the problem of grand unification; namely, the contemporary use of Schwinger functions as a symmetry-preserving tool for the unified explanation and prediction of the properties of both mesons and baryons. It reveals that DCSB drives the formation of diquark clusters in baryons and sketches a picture of baryons as bound-states with Borromean character. Planned experiments are capable of validating the perspectives outlined in these lectures.