A QCD sum rules calculation of the J/ψDs*Ds strong coupling constant

In this work, we calculate the form factors and the coupling constant of the strange-charmed vertex J/ψDs*Ds in the framework of the QCD sum rules by studying their three-point correlation functions. All the possible off-shell cases are considered, Ds, Ds* and J/ψ, resulting in three different form factors. These form factors are extrapolated to the pole of their respective off-shell mesons, giving the same coupling constant for the process. Our final result for the J/ψDs*Ds coupling constant is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$g_{J/\psi D_s^* D_s } = 4.30_{ - 1.22}^{ + 1.53} GeV^{ - 1}$$\end{document}.