Analysis of the X(1576) as a tetraquark state with the QCD sum rules
  In this letter, we take the point of view that the X(1576) be tetraquark state which consists of a scalar-diquark and an anti-scalar-diquark in relative $P$-wave, and calculate its mass in the framework of the QCD sum rules approach. The numerical value of the mass $m_X=(1.66\pm 0.14) GeV$ is consistent with the experimental data, there may be some tetraquark component in the vector meson X(1576). 
Zhi-Gang Wang (NCEPU, Baoding), Shao-Long Wan