Resonance X(5568) as an exotic axial-vector state

Abstract.

The mass and meson-current coupling constant of the resonance $X(5568)$, as well as the width of the decay $X(5568)\rightarrow B_{s}^{\ast}\pi$ are calculated by modeling the exotic X(5568) resonance as a diquark-antidiquark state $X_{b}=[su][bd]$ with quantum numbers $J^{P}=1^{+}$. The calculations are made employing QCD two-point sum rule method, where the quark, gluon and mixed vacuum condensates up to dimension eight are taken into account. The sum rule approach on the light-cone in its soft-meson approximation is used to explore the vertex $X_{b}B_{s}^{\ast}\pi$ and extract the strong coupling $g_{X_{b}B_{s}^{\ast}\pi}$, which is a necessary ingredient to find the width of the $X_{b}\rightarrow B_{s}^{\ast}\pi^{+}$ decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.