Yang--Mills Glueballs as Closed Bosonic Strings

TL;DR

This paper introduces the Axionic String Ansatz (ASA), a unified string-based model for describing confining strings and glueball spectra in pure Yang--Mills theory in 3D and 4D, aligning well with lattice data.

Contribution

The paper proposes the ASA, a novel string-theoretic framework that predicts glueball quantum numbers and spectra consistent with lattice measurements in Yang--Mills theory.

Findings

Good agreement between ASA predictions and lattice glueball data in 3D.

Identification of a massive pseudoscalar mode in 4D glueball spectrum.

ASA provides a unified description of confining strings in different dimensions.

Abstract

We put forward the Axionic String Ansatz (ASA), which provides a unified description for the worldsheet dynamics of confining strings in pure Yang--Mills theory both in $D=3$ and $D=4$ space-time dimensions. The ASA is motivated by the excitation spectrum of long confining strings, as measured on a lattice, and by recently constructed integrable axionic non-critical string models. According to the ASA, pure gluodynamics in 3D is described by a non-critical bosonic string theory without any extra local worldsheet degrees of freedom. We argue that this assumption fixes the set of quantum numbers (spins, $P$- and $C$-parities) of almost all glueball states. We confront the resulting predictions with the properties of approximately $1^2+2^2+3^2+5^2=39$ lightest glueball states measured on a lattice and find a good agreement. On the other hand, the spectrum of low lying glueballs in 4D gluodynamics suggests the presence of a massive pseudoscalar mode on the string worldsheet, in agreement with the ASA and lattice data for long strings.