On the $\eta'$ Gluonic Admixture

TL;DR

This paper investigates the potential gluonic component of the eta' meson, analyzing experimental data to estimate its size and impact on specific decay processes, suggesting a significant gluonium admixture.

Contribution

It provides a quantitative analysis of the eta' gluonic admixture and highlights its influence on J/psi decay amplitudes, offering new insights into meson structure.

Findings

Eta' may contain up to 26% gluonium component.

Gluonium significantly contributes to J/psi -> eta' gamma decay.

Experimental data supports a notable gluonic admixture in eta'.

Abstract

The $\eta'$ which is an $SU(3)_F$ singlet state can contain a pure gluon component, gluonium. We examine this possibility by analysing all available experimental data. It is pointed out that the $\eta'$ gluonic component may be as large as 26%. We also show that the amplitude for $J/\psi -> \eta'\gamma$ decay obtains a notable contribution from gluonium.