A note on the fate of the Landau-Yang theorem in non-Abelian gauge theories

TL;DR

This paper explores how the Landau-Yang theorem, which forbids certain decays, is modified in non-Abelian gauge theories, showing that a massive color-octet vector can decay into two gluons under specific conditions.

Contribution

It demonstrates that the Landau-Yang theorem does not universally apply in non-Abelian SU(N) theories and clarifies the conditions allowing such decays.

Findings

Decay of a massive color-octet vector into two gluons is possible.

Constraints on the decay amplitude are derived from symmetry considerations.

Effective-action operators provide a simple understanding of the results.

Abstract

Using elementary considerations of Lorentz invariance, Bose symmetry and BRST invariance, we argue why the decay of a massive color-octet vector state into a pair of on-shell massless gluons is possible in a non-Abelian SU(N) Yang-Mills theory, we constrain the form of the amplitude of the process and offer a simple understanding of these results in terms of effective-action operators.