A novel configuration of gluonic tetraquark state

TL;DR

This paper uses QCD sum rules to calculate the masses of gluonic tetraquark hybrid states, providing theoretical support for interpreting the X(6900) as a tetracharm hybrid and predicting bottom sector states for future experiments.

Contribution

It introduces a novel calculation of gluonic tetraquark hybrid masses with specific quantum numbers, extending the understanding of exotic hadrons in QCD.

Findings

Charm sector tetracharm hybrid with $0^{++}$ has a mass around 6.98 GeV.

Charm sector $0^{-+}$ state has a mass around 7.26 GeV.

Predicted bottom sector hybrid masses are approximately 19.30 GeV and 19.50 GeV.

Abstract

Inspired by the experimental measurement of the charmed hadronic state X(6900), we calculate the mass spectra of tetraquark hybrid states with configuration of \([8_{c}]_{Q\bar{Q}} \otimes [8_{c}]_{G} \otimes [8_{c}]_{Q\bar{Q}}\) in color, by virtue of QCD sum rules. The two feasible types of currents with quantum numbers $J^{PC} = 0^{++}$ and $0^{-+}$ are investigated, in which the contributions from operators up to dimension six are taken into account in operator product expansion (OPE). In the end, we find that, in charm sector, the tetracharm hybrid states with quantum number \(0^{++}\) has a mass of about \(6.98^{+0.16}_{-0.14} \, \text{GeV}\), while \(0^{-+}\) state mass is about \(7.26^{+0.16}_{-0.15} \, \text{GeV}\). The results overlap with the experimental observations, suggesting potential tetracharm hybrid interpretations. In bottom sector, calculation shows that the masses of tetrabottom hybrid states with quantum numbers $0^{++}$ and $0^{-+}$ are \(19.30^{+0.16}_{-0.17} \, \text{GeV}\) and \(19.50^{+0.17}_{-0.17} \, \text{GeV}\), respectively, which are left for future experimental confirmation.