50 Years of Quantum Chromodynamics

TL;DR

This comprehensive review traces the development, key concepts, and experimental validations of Quantum Chromodynamics over 50 years, highlighting theoretical foundations, computational methods, and future experimental prospects.

Contribution

It provides an extensive synthesis of QCD's theoretical and experimental progress, including lattice QCD, effective theories, and collider measurements, serving as a foundational resource for new researchers.

Findings

Lattice QCD enables exact predictions of hadronic properties.

Effective field theories approximate QCD in various regimes.

Experimental data from colliders confirm key QCD predictions.

Abstract

This paper presents a comprehensive review of both the theory and experimental successes of Quantum Chromodynamics, starting with its emergence as a well defined theory in 1972-73 and following developments and results up to the present day. Topics include a review of the earliest theoretical and experimental foundations; the fundamental constants of QCD; an introductory discussion of lattice QCD, the only known method for obtaining exact predictions from QCD; methods for approximating QCD, with special focus on effective field theories; QCD under extreme conditions; measurements and predictions of meson and baryon states; a special discussion of the structure of the nucleon; techniques for study of QCD at high energy, including treatment of jets and showers; measurements at colliders; weak decays and quark mixing; and a section on the future, which discusses new experimental facilities or upgrades currently funded. The paper is intended to provide a broad background for Ph.D. students and postdocs starting their career. Some contributions include personal accounts of how the ideas or experiments were developed.