On the Quantum Chromodynamics of a Massive Vector Field in the Adjoint Representation

TL;DR

This paper investigates the quantum properties of a massive color-octet vector field in QCD, demonstrating how unitarity constrains couplings and introduces a symmetry that stabilizes the particle, without relying on extended gauge structures.

Contribution

It shows that unitarity alone can determine coupling constants and stabilize the massive vector field, offering a novel approach without extended gauge symmetries or scalar fields.

Findings

Unitarity fixes the coupling constants of the massive vector field.

A new discrete symmetry stabilizes the color-octet vector, preventing resonant production.

Modified gauge fixing terms improve the UV behavior of the propagator.

Abstract

In this paper, we explore the possibility of constructing the quantum chromodynamics of a massive color-octet vector field without introducing higher structures like extended gauge symmetries, extra dimensions or scalar fields. We show that gauge invariance is not enough to constraint the couplings. Nevertheless the requirement of unitarity fixes the values of the coupling constants, which otherwise would be arbitrary. Additionally, it opens a new discrete symmetry which makes the coloron stable and avoid its resonant production at a collider. On the other hand, a judicious definition of the gauge fixing terms modifies the propagator of the massive field making it well-behaved in the ultra-violet limit. The relation between our model and the more general approach based on extended gauge symmetries is also discussed.