QCD sum rule studies on the sss¯ s¯ tetraquark states of JPC= 0 - +

Abstract

We apply the method of QCD sum rules to study the sss¯ s¯ tetraquark states of JPC= 0 - +. We construct all the relevant sss¯ s¯ tetraquark currents, and find that there are only two independent ones. We use them to further construct two weakly-correlated mixed currents. One of them leads to reliable QCD sum rule results and the mass is extracted to be 2.51-0.12+0.15 GeV, suggesting that the X(2370) or the X(2500) can be explained as the sss¯ s¯ tetraquark state of JPC= 0 - +. To verify this interpretation, we propose to further study the ππ/ KK¯ invariant mass spectra of the J/ ψ→ γππη′/ γKK¯ η′ decays in BESIII to examine whether there exists the f(980) resonance.