BsB⁎K and BsBK⁎ vertices using QCD sum rules

The form factors and the coupling constant of the BsB⁎K and BsBK⁎ vertices are calculated using the QCD sum rules method. Three-point correlation functions are computed considering both the heavy and light mesons off-shell in each vertex, from which, after an extrapolation of the QCDSR results at the pole of the off-shell mesons, we obtain the coupling constant of the vertex. The form factors obtained have different behaviors but their simultaneous extrapolation reaches the same value of the coupling constant, gBsB⁎K=8.41±1.23 and gBsBK⁎=3.3±0.5. We compare our result with other theoretical estimates and compute the uncertainties of the method.