Light double-gluon hybrid states from QCD sum rules

TL;DR

This paper uses QCD sum rules to predict the masses and decay patterns of double-gluon hybrid states with specific quantum numbers, expanding understanding of exotic hadrons.

Contribution

It constructs new double-gluon hybrid currents and calculates their masses for the first time using QCD sum rules, especially for the exotic $J^{PC} = 2^{+-}$ states.

Findings

Mass of $ar q q gg; 2^{+-}$ state is approximately 2.26 GeV.

Mass of $ar s s gg; 2^{+-}$ state is approximately 2.38 GeV.

Decay patterns suggest possible experimental signatures.

Abstract

We study the double-gluon hybrid states with the quark-gluon contents $\bar q q gg$ ($q=u/d$) and $\bar s s gg$. We construct twelve double-gluon hybrid currents with various quantum numbers, five of which are found to be zero due to some internal symmetries between the two gluon fields. We use the rest seven currents to perform QCD sum rule analyses. Especially, the masses of the double-gluon hybrid states with the exotic quantum number $J^{PC} = 2^{+-}$ are calculated to be $M_{|\bar q q gg;2^{+-}\rangle} = 2.26^{+0.20}_{-0.25}$ GeV and $M_{|\bar s s gg;2^{+-}\rangle} = 2.38^{+0.19}_{-0.25}$ GeV. Their two- and three-meson decay patterns are also investigated.