Analysis of the strong decay $X(5568) \to B_s^0\pi^+$ with QCD sum rules
  In this article, we take the $X(5568)$ to be the scalar diquark-antidiquark type tetraquark state, study the hadronic coupling constant $g_{XB_s\pi}$ with the three-point QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension-6 and including both the connected and disconnected Feynman diagrams, then calculate the partial decay width of the strong decay $ X(5568) \to B_s^0 \pi^+$ and obtain the value $\Gamma_X=\left(20.5\pm8.1\right)\,\rm{MeV}$, which is consistent with the experimental data $\Gamma_X = \left(21.9 \pm 6.4 {}^{+5.0}_{-2.5}\right)\,\rm{MeV}$ from the D0 collaboration. 
Zhi-Gang Wang
hep-ph