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 the 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.

Figure 1

The mass $m_{X_b}$ as a function of the Borel parameter $M^2$ for different values of $s_0$.

Figure 2

The decay constant $f_{X_b}$ vs Borel parameter $M^2$. The values of the parameter $s_0$ are shown in the figure.