Gauge field spectrum in massive Yang-Mills theory with Lorentz violation

TL;DR

This paper analyzes the spectrum of a massive Yang-Mills theory with Lorentz violation, demonstrating that causality can be maintained and a physical, unitary sector can be defined at tree-level.

Contribution

It provides a detailed spectrum analysis of CPT-odd Lorentz-violating Yang-Mills theory, showing how causality constrains the physical sector and suggesting unitarity with ghost inclusion.

Findings

Causality constrains the physical sector of the gauge propagator.

A consistent spectrum can be defined despite Lorentz violation.

The model is expected to be unitary when ghosts are included.

Abstract

The spectrum of the massive CPT-odd Yang-Mills propagator with Lorentz violation is performed at tree-level. The modification is due to mass terms generated by the exigence of multiplicative renormalizability of Yang-Mills theory with Lorentz violation. The causality analysis is performed from group and front velocities for both, spacelike and timelike background tensors. It is show that, by demanding causality, it is always possible to define a physical sector for the gauge propagator. Hence, it is expected that the model is also unitary, if one takes the Faddeev-Popov ghost into account.