Strong coupling constant of vector bottomonium to the pseudoscalar and vector B_c mesons via QCD sum rules

The strong coupling constant $g_{\Upsilon B_c^{ps} B_c^V}$ is evaluated using the three-point QCD sum rules. The correlation functions used to calculate these strong coupling constants contain contributions of both $B_c^V$ and $B_c^{ps}$ mesons as off-shell states with contributions of two gluon condensates as a radiative corrections. The results, $g_{\Upsilon B_c^V B_c^{PS}}=1.67\pm 0.52 GeV^{-1}$ for $B_c^{Ps}$ off-shell and $g_{\Upsilon B_c^{PS}B_c^V}=(0.87\pm0.25) GeV^{-1}$ for $B_c^V$ off-shell are obtained for the relevant strong coupling constants