Mass spectrum of gapped, non-confining theories with multi-scale dynamics

TL;DR

This paper investigates the mass spectrum of composite states in three-dimensional theories with multi-scale dynamics, revealing how non-confining theories can exhibit a mass gap and how spectra interpolate near conformal fixed points.

Contribution

It provides a detailed analysis of the mass spectrum in non-confining, multi-scale theories using supergravity duals, highlighting the conditions for light pseudo-dilatons.

Findings

Mass gap exists despite non-confinement.

Spectrum interpolates between conformal and quasi-confining regimes.

Deep IR effects lift the mass of potential pseudo-dilatons.

Abstract

We study the mass spectrum of spin-0 and spin-2 composite states in a one-parameter family of three-dimensional field theories by making use of their dual descriptions in terms of supergravity. These theories exhibit a mass gap despite being non-confining, and by varying a parameter can be made to flow arbitrarily close to an IR fixed point corresponding to the Ooguri-Park conformal field theory. At the opposite end of parameter space, the dynamics becomes quasi-confining. The glueball spectrum interpolates between these two limiting cases, and for nearly conformal dynamics approaches the result of the Ooguri-Park theory deformed by a relevant operator. In order to elucidate under which circumstances quasi-conformal dynamics leads to the presence of a light pseudo-dilaton, we perform a study of the dependence of the spectrum on the position of a hard-wall IR cutoff and find that, in the present case, the mass of such state is lifted by deep-IR effects.