Bs1⁎B⁎K form factor from QCD sum rules

In this article, we calculate the form factors and the coupling constant of the gBs1⁎B⁎K vertex in the framework of the three-point QCD sum rules. Three point correlation functions responsible for the vertex are evaluated by considering both B⁎ and K mesons as off-shell states. The form factors obtained are different if the B⁎ or the K meson is off-shell but give the same coupling constant.