William A. Bardeen -- A Brief Biography

TL;DR

William A. Bardeen was a pioneering theoretical physicist known for foundational contributions to anomalies, quantum chromodynamics, and electroweak symmetry breaking, significantly influencing high-energy physics theories.

Contribution

The paper highlights Bardeen's key theoretical advancements, including the Adler-Bardeen theorem, non-Abelian anomalies, and models of electroweak symmetry breaking.

Findings

Established the Adler-Bardeen theorem

Developed theories on non-Abelian and gravitational anomalies

Predicted long-lived heavy-light quark resonances

Abstract

William Allan Bardeen (September 15, 1941 $-$ November 18, 2025) was an American theoretical physicist who worked at the Fermi National Accelerator Laboratory. He is renowned for his foundational work on the chiral anomaly, the Adler-Bardeen theorem, the non-Abelian anomaly and gravitational anomalies. He was instrumental in the development of quantum chromodynamics and its applications, such as semileptonic decays and the $\Lambda_{\overline{MS}}$ scheme frequently used in perturbative analysis of high energy processes involving strong interactions. Bardeen also played a major role in developing a theory of dynamical breaking of electroweak symmetry via top quark condensates, leading to one of the first composite Brout-Englert-Higgs boson models. His work on the chiral symmetry dynamics of heavy-light quark bound states correctly predicted abnormally long-lived resonances which are chiral symmetry partners of the ground state.