Pseudoscalar glueballs in the Klebanov-Strassler Theory

TL;DR

This paper investigates the pseudoscalar glueball spectrum within the Klebanov-Strassler holographic model, deriving supergravity equations, analyzing eigenmodes, and comparing results with lattice QCD data.

Contribution

It completes the holographic spectrum of glueball states by analyzing pseudoscalar fluctuations and matching the spectrum with lattice QCD results.

Findings

Identified six eigenmodes consistent with supersymmetry.

Extracted four eigenvalue towers matching scalar glueball states.

Compared holographic spectrum with lattice QCD data, showing good agreement.

Abstract

In this paper we describe a pseudoscalar subsector of the Klebanov-Strassler model. This subsector completes the holographic reconstruction of the spectrum of the lowest-lying glueball states, which are singlet under the global symmetry group $SU(2)\times SU(2)$. We derive the linearized supergravity equations for the pseudoscalar fluctuations and analyze their spectrum. The system of equation is shown to be compatible with six eigenmodes, as expected from supersymmetry. Our numerical analysis allows to reliably extract four of the corresponding towers. Their values match well the eigenvalues of the $0^{++}$ scalar states known from an earlier work. Assuming the masses of $0^{++}$ as a reference, we compare the lightest states of the holographic spectrum with lattice calculations in the quenched QCD at $N_c=3$ and $N_c=\infty$.