Emergence of Hadron Mass and Structure

TL;DR

This paper discusses how the mass of protons and hadrons emerges from quantum chromodynamics (QCD) through nonperturbative methods, highlighting recent progress in understanding the fundamental origin of visible matter's mass.

Contribution

It presents recent advancements in applying continuum Schwinger function methods to elucidate the mechanisms behind emergent hadron mass in QCD.

Findings

Identification of the running gluon mass as key to mass generation

Development of process-independent effective charge in QCD

Demonstration of measurable effects of running quark mass

Abstract

Visible matter is characterised by a single mass scale; namely, the proton mass. The proton's existence and structure are supposed to be described by quantum chromodynamics (QCD); yet, absent Higgs boson couplings, chromodynamics is scale invariant. Thus, if the Standard Model is truly a part of the theory of Nature, then the proton mass is an emergent feature of QCD; and emergent hadron mass (EHM) must provide the basic link between theory and observation. Nonperturbative tools are necessary if such connections are to be made; and in this context, we sketch recent progress in the application of continuum Schwinger function methods to an array of related problems in hadron and particle physics. Special emphasis is given to the three pillars of EHM -- namely, the running gluon mass, process-independent effective charge, and running quark mass; their role in stabilising QCD; and their measurable expressions in a diverse array of observables.