The Discovery of the Gluon

TL;DR

This paper recounts the theoretical prediction and experimental discovery of the gluon, highlighting the search for gluon signatures in electron-positron collisions which led to its confirmation in 1979.

Contribution

It documents the first experimental evidence of the gluon, confirming a key prediction of quantum chromodynamics and advancing particle physics understanding.

Findings

Gluon was experimentally discovered in 1979.

3-jet events in $e^+ e^-$ collisions serve as evidence for gluons.

The discovery confirmed the existence of gluons as force carriers in QCD.

Abstract

Soon after the postulation of quarks, it was suggested that they interact via gluons, but direct experimental evidence was lacking for over a decade. In 1976, Mary Gaillard, Graham Ross and the author suggested searching for the gluon via 3-jet events due to gluon bremsstrahlung in $e^+ e^-$ collisions. Following our suggestion, the gluon was discovered at DESY in 1979 by TASSO and the other experiments at the PETRA collider.