Analysis of 0++ nonet mesons as four-quark states with QCD sum rules

In this paper, we take the point of view that the O++ nonet mesons below 1 GeV are diquark-antidiquark states (qq)((3) over bar) ((q) over bar(q) over bar (3) and seek to determine their masses in the framework of the QCD sum rules approach with the interpolating currents constructed from scalar-scalar-type and pseudoscalar-pseudoscalar-type diquark pairs respectively. The numerical results indicate that the O++ nonet mesons may have two possible diquark-antidiquark substructures.