Fully charmed tetraquark states in 8[c(c)over-bar]⊗8[c(c)over-bar]color structure viaQCD sum rules

Stimulated 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 (c) over bar])circle times 8([c (c) over bar])color configuration via QCD sum rules. By constructing nine 8([c (c) over bar])circle times 8([c (c) over bar]) type currents with quantum numbers J(PC)=0(-+),0(--),1(-+),1(+-),1(--)and 2(++),we perform analytic calculation up to dimension six in the operator product expansion (OPE). We find the fully-charm tetra quark states with J(PC)=1(+-),2(++) lie around 6.48 similar to 6.62 GeV while the fully-charm tetraquark states with J(PC)=0(-+),0(--),1(--),1(-+) are about 6.85 similar to 7.02 GeV. Notably, the mass predictions for the c (c) over barc (c) over bar tetra quarks, specifically those with J(PC)=2(++), align with the broad structure identified by LHCb. Moreover, the masses of fully-charm tetraquarks with J(PC)=0(-+)and 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 (c) over bar])circle times 8([c (c) over bar])components within the di-J/psi struc-tures observed by LHCb. The predictions for tetraquark states with J(PC)=0(--),1(+-),1(--) may be accessible in the future BelleII, Super-B, PANDA, and LHCb experiments.