Mass and decay constant of the newly observed exotic $X(5568)$ state
  The mass and decay constant of the $X(5568)$ state newly observed by D0 Collaboration are computed within the two-point sum rule method using the diquark-antidiquark interpolating current. In calculations, the vacuum condensates up to eight dimensions are taken into account. The obtained result for the mass of the $X(5568)$ state is in a nice agreement with the experimental data. 
S. S. Agaev, K. Azizi, H. Sundu
hep-ph hep-ex hep-lat