Constituent gluon interpretation of glueballs and gluelumps

TL;DR

This paper supports interpreting glueballs and gluelumps as bound states of massless gluons with helicity-1, explaining their mass hierarchy and predicting the nature of the 0^{+-} glueball using a flux tube model.

Contribution

It introduces a constituent gluon model with helicity-1 to interpret lattice QCD spectra of glueballs and gluelumps, providing a flux tube model for mass calculations.

Findings

Mass hierarchy explained by number of constituent gluons

0^{+-} glueball likely a four-gluon bound state

Flux tube model's mass predictions agree with lattice QCD

Abstract

Arguments are given that support the interpretation of the lattice QCD glueball and gluelump spectra in terms of bound states of massless constituent gluons with helicity-1. In this scheme, the mass hierarchy of the currently known gluelumps and glueballs is mainly due to the number of constituent gluons and can be understood within a simple flux tube model. It is also argued that the lattice QCD $0^{+-}$ glueball should be seen as a four-gluon bound state. The flux tube model allows for a parameter-free computation of its mass, which is in good agreement with lattice QCD.