The form factor and the coupling constant in the $\eta_{ b}BB^{ \ast}$ vertex are evaluated in the framework of three-point QCD sum rules. The correlation functions responsible for the vertex is evaluated considering contributions of both $B$ and $B^{ \ast}$ mesons as off-shell states. The form factors obtained are different for the two cases, whereas the final results of the coupling constant are compatible.
Categories: hep-ph