An axion-like mechanism for confinement in QCD

TL;DR

This paper proposes that confinement in QCD can be explained by a topological vacuum structure that does not correspond to the $ heta$-vacuum, and that an axion-like mechanism can describe the confined phase.

Contribution

It introduces a novel topological condition for confinement in QCD and demonstrates that an axion-like mechanism can model the confined phase.

Findings

Confinement occurs if the QCD vacuum does not match the $ heta$-vacuum.

An axion-like mechanism can effectively describe the confined phase.

Topological vacuum structure is key to understanding confinement in QCD.

Abstract

This letter is about confinement in QCD. At the moment we have pictures of confinement to complete our understanding of the physics of strongly interacting particles, interaction which asks for confinement. As it is said in [1] : " In principle it should be possible to derive the confinement hypothesis from the QCD Lagrangian. At this time, no rigorous derivation exists, so it is not absolutely clear that the confinement hypothesis is a bone fide prediction of QCD". In this letter we show that a sufficient (of course not necessary) condition for confinement is that topological structure of vacuum in Nature does not correspond to the $\theta$-vacuum. Therefore, if different vacua with nontrivial winding number cannot be connected by tunneling, we obtain confinement as a consequence. Moreover, we show that an axion-like mechanism would suffice to describe a confined QCD phase.