Eur. Phys. J. Special Topics 229, 3319–3340 (2020)
https://doi.org/10.1140/epjst/e2020-000064-6

Review

Reflections upon the emergence of hadronic mass

¹ School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
² Institute for Nonperturbative Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
³ RWTH Aachen University, III. Physikalisches Institut B, Aachen 52074, Germany
⁴ Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01314, Germany

^a e-mail: cdroberts@nju.edu.cn
^b e-mail: s.schmidt@hzdr.de

Received: 11 April 2020
Accepted: 27 October 2020
Published online: 21 December 2020

Abstract

With discovery of the Higgs boson, science has located the source for ≲2% of the mass of visible matter. The focus of attention can now shift to the search for the origin of the remaining ≳98%. The instruments at work here must be capable of simultaneously generating the 1 GeV mass-scale associated with the nucleon and ensuring that this mass-scale is completely hidden in the chiral-limit pion. This hunt for an understanding of the emergence of hadronic mass (EHM) has actually been underway for many years. What is changing are the impacts of QCD-related theory, through the elucidation of clear signals for EHM in hadron observables, and the ability of modern and planned experimental facilities to access these observables. These developments are exemplified in a discussion of the evolving understanding of pion and kaon parton distributions.