Glueball Spectrum in a Gauge Theory with Two Dynamical Scales

TL;DR

This paper uses gauge/gravity duality to analytically compute the glueball spectrum in a strongly coupled gauge theory with two dynamical scales, revealing a hierarchy between confinement and chiral symmetry breaking scales.

Contribution

It provides the first analytical computation of the glueball spectrum in a two-scale gauge theory with a gravitational dual, highlighting the absence of a light state and the hierarchy of physical scales.

Findings

No light glueball state associated with near-conformal behavior.

A significant hierarchy exists between confinement and chiral symmetry breaking scales.

Analytical results for the glueball spectrum in a two-scale gauge theory.

Abstract

We investigate the glueball spectrum of a strongly coupled gauge theory with two dynamical scales. The main tool is the use of the gauge/gravity duality. The model we study has a known graviational dual, which arises from a type IIB D-brane configuration. It exhibits two dynamical scales, separated by a nearly conformal region. Thus, it is of great interest for the study of walking in gauge theories. By using the gravitational description, we are able to compute analytically the glueball mass spectrum in a certain range of the parameter space of the theory. Within that range, we do not find a light state that could be associated with a slight breaking of conformal invariance. Finally, we show that in this model there can be an order of magnitude hierarchy between the scale of confinement, given by the lowest glueball mass, and the scale of chiral symmetry breaking, determined by the lowest vector-meson mass.