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)→Bs*π are calculated by modeling the exotic X(5568) resonance as a diquark-antidiquark state Xb= [su] [ bd] with quantum numbers JP= 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 XbBs*π and extract the strong coupling gXbBs*π, which is a necessary ingredient to find the width of the Xb→Bs*π+ decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.