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 $X(5568)\to B_s^{\ast }\pi$ are calculated by modeling the exotic $X(5568)$ resonance as a diquark-antidiquark state 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 , which is a necessary ingredient to find the width of the $X_b\to B_s^{\ast }{\pi }^{+}$ decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.

Comments: 10 Pages, 5 Figures and 1 Table