Fully charmed tetraquark states in $$8_{[c\bar{c}]}\otimes 8_{[c\bar{c}]}$$ color structure via QCD sum rules

Abstract

AbstractStimulated by the recent experimental results on the fully-charm tetraquark states, we systematically calculate the mass spectra of the fully-charm tetraquark states in $$8_{[c\bar{c}]}\otimes 8_{[c\bar{c}]}$$ 8 [ c c ¯ ] ⊗ 8 [ c c ¯ ] color configuration via QCD sum rules. By constructing nine $$8_{[c\bar{c}]}\otimes 8_{[c\bar{c}]}$$ 8 [ c c ¯ ] ⊗ 8 [ c c ¯ ] type currents with quantum numbers $$J^{PC}=0^{-+},0^{--},1^{-+},1^{+-},1^{--}$$ J PC = 0 - + , 0 - - , 1 - + , 1 + - , 1 - - and $$2^{++}$$ 2 + + , we perform analytic calculation up to dimension six in the operator product expansion (OPE). We find the fully-charm tetraquark states with $$J^{PC}=1^{+-},2^{++}$$ J PC = 1 + - , 2 + + lie around 6.48 $$\sim $$ ∼ 6.62 GeV while the fully-charm tetraquark states with $$J^{PC}=0^{-+},0^{--},1^{--},1^{-+}$$ J PC = 0 - + , 0 - - , 1 - - , 1 - + are about 6.85 $$\sim $$ ∼ 7.02 GeV. Notably, the mass predictions for the $$c\bar{c}c\bar{c}$$ c c ¯ c c ¯ tetraquarks, specifically those with $$J^{PC}=2^{++}$$ J PC = 2 + + , align with the broad structure identified by LHCb. Moreover, the masses of fully-charm tetraquarks with $$J^{PC}=0^{-+}$$ J PC = 0 - + and $$1^{-+}$$ 1 - + are anticipated to match closely with the mass of X(6900), considering the margin of error. Such findings hint at the presence of some $$8_{[c\bar{c}]}\otimes 8_{[c\bar{c}]}$$ 8 [ c c ¯ ] ⊗ 8 [ c c ¯ ] components within the di-$$J/\psi $$ J / ψ structures observed by LHCb. The predictions for tetraquark states with $$J^{PC}=0^{--},1^{+-},1^{--}$$ J PC = 0 - - , 1 + - , 1 - - may be accessible in the future BelleII, Super-B, PANDA, and LHCb experiments.