Analysis of the Q Q (Q)over-bar (Q)over-bar tetraquark states with QCD sum rules

In this article, we study the J(PC) = 0(++) and 2(++) Q Q (Q) over bar (Q) over bar tetraquark states with the QCD sum rules, and we obtain the predictions M-X(c c (c) over bar (c) over bar 0(++) = 5.99 +/- 0.08 GeV, M-X(c c (c) over bar (c) over bar, 2(++)) = 6.09 +/- 0.08 GeV, M-X(b b (b) over bar (b) over bar, 0(++) = 18.84 +/- 0.09 GeV M-X(b b (b) over bar (b) over bar, 2(++) = 18.85 +/- 0.09 GeV which can be confronted to the experimental data in the future. Furthermore, we illustrate that the diquark-antidiquark type tetraquark state can be taken as a special superposition of a series of meson-meson pairs and that it embodies the net effects.