The $g_{J\mathrm{/}\psi D_s{D}_s}$ strong coupling constant from QCD Sum Rules

The coupling constant of the meson vertex $J\mathrm{/}\psi D_s{D}_s$ is calculated using the three point correlation function within the QCD Sum Rule formalism. We have considered alternately mesons $J\mathrm{/}\psi$ and $D_s$ off-shell together with non-perturbative contributions up to the mixed quark-gluon condensates. When extrapolated, these two different form factors give the same coupling constant for the process $g_{J\mathrm{/}\psi D_s{D}_s}=5.98_{-0.58}^{+0.67}$.