Gluonic excitation of non-exotic hybrid charmonium from lattice QCD

TL;DR

This study uses lattice QCD to investigate non-exotic hybrid charmonium states, revealing significant gluonic excitations and predicting their masses, which differ from conventional charmonium, with implications for experimental discoveries like Y(4260).

Contribution

First lattice QCD investigation of non-exotic hybrid charmonium states with specific quantum numbers, highlighting gluonic excitations and providing mass predictions.

Findings

Strong gluonic radial excitations observed in first excited states.

Predicted masses are 4.352(225) GeV, 4.379(149) GeV, and 7.315(257) GeV.

Masses differ significantly from conventional charmonium excited states.

Abstract

The ground and first excited states of the hybrid charmonium ${\bar c} c g$, with non-exotic quantum numbers $J^{PC}=0^{-+}$, $1^{--}$ and $1^{++}$ are investigated using quenched lattice QCD. They are completely ignored in the literature, only because their ground states are degenerate with $\eta_c$, $J/\psi$, and $\chi_{c1}$, and are difficult to be distinguished from these conventional charmonium mesons in experiment. However, we observe strong gluonic radial excitations in the first excited states; We predict that their masses are 4.352(225)GeV, 4.379(149)GeV and 7.315(257)GeV, completely different from the first excited states of the corresponding conventional charmonium. Their relevance to the recent discovery of the Y(4260) state and future experimental search for other states are also discussed.