Two-gluon and trigluon glueballs from dynamical holography QCD

TL;DR

This paper models scalar, vector, and tensor two-gluon and trigluon glueball spectra using a 5D dynamical holographic QCD framework, achieving good agreement with lattice data and providing insights into glueball composition.

Contribution

It introduces a self-consistent dynamical holographic QCD model with only one free parameter to predict glueball spectra, including distinctions between even and odd parity states.

Findings

Two-gluon glueball spectra match lattice data.

Certain trigluon glueball masses agree with lattice results.

Some trigluon glueball masses are lighter, suggesting three-gluon condensate dominance.

Abstract

We study the scalar, vector and tensor two-gluon and trigluon glueball spectra in the framework of 5-dimension dynamical holographic QCD model, where the metric structure is deformed self-consistently by the dilaton field. For comparison, the glueball spectra are also calculated in the hard-wall and soft-wall holographic QCD models. In order to distinguish glueballs with even and odd parities, we introduce the positive and negative coupling between the dilaton field and glueballs, and for higher spin glueballs, we introduce a deformed 5-dimension mass. With this set-up, there is only one free parameter from the quadratic dilaton profile in the dynamical holographic QCD model, which is fixed by the scalar glueball spectra. It is found that the two-gluon glueball spectra produced in the dynamical holographic QCD model are in good agreement with lattice data. Among six trigluon glueballs, the produced masses for $1^{\pm -}$ and $2^{--}$ are in good agreement with lattice data, and the produced masses for $0^{--}$, $0^{+-}$ and $2^{+-}$ are around 1.5 {\rm GeV} lighter than lattice results. This result might indicate that the three trigluon glueballs of $0^{--}$, $0^{+-}$ and $2^{+-}$ are dominated by three-gluon condensate contribution.