Predictions for production and decay of the pseudoscalar glueball from the Witten-Sakai-Sugimoto model

TL;DR

This paper uses the Witten-Sakai-Sugimoto model to predict the production and decay characteristics of the pseudoscalar glueball, providing specific decay pattern predictions based on a top-down holographic QCD approach.

Contribution

It offers new quantitative predictions for the decay modes of the pseudoscalar glueball using a string theory-inspired holographic model, connecting to the U(1)_A problem.

Findings

Predicted decay patterns for the pseudoscalar glueball.

Identified the narrow width of the pseudoscalar glueball.

Linked the model's predictions to the U(1)_A problem.

Abstract

The Witten-Sakai-Sugimoto model, a top-down gauge/gravity model of large-$N_c$ low-energy QCD based on type-IIA string theory and $N_c$ D4 branes with chiral quarks added by probe D8 branes, involves only one dimensionless parameter, the 't Hooft coupling at its cutoff (Kaluza-Klein) scale. Although this cutoff scale is around 1 GeV, the model has turned out to be surprisingly predictive also quantitatively, reproducing masses of vector and axial vector mesons, their decay rates, as well as the anomalous mass of the \eta' meson, all within 10-30% errors. Using it as a guide for glueball signatures, we have argued that it indicates that the meson $f_0(1710)$ may be a nearly pure glueball, with rather specific predictions for the still-to-be-measured 4\pi and \eta\eta' decays. Here we present our new predictions for the decay pattern of the (very narrow) pseudoscalar glueball, which is closely related to the U(1)$_A$ problem that the model is in fact handling correctly.