A QCD sum rules calculation of the $J/\psi D_s^* D_s$ strong coupling constant

TL;DR

This paper uses QCD sum rules to calculate the strong coupling constant for the $J/\psi D_s^* D_s$ vertex, considering all off-shell cases and extrapolating form factors to determine a consistent coupling value.

Contribution

It provides a novel calculation of the $J/\psi D_s^* D_s$ coupling constant using three-point correlation functions in QCD sum rules, considering multiple off-shell scenarios.

Findings

Calculated the coupling constant as $4.30^{+0.42}_{-0.37}$ GeV$^{-1}$.

Derived form factors for all off-shell cases and extrapolated to the meson poles.

Confirmed consistency of the coupling constant across different off-shell configurations.

Abstract

In this work, we calculate the form factors and the coupling constant of the strange-charmed vertex $J/\psi D_s^* D_s$ in the framework of the QCD sum rules by studying their three-point correlation functions. All the possible off-shell cases are considered, $D_s$, $D_s^*$ and $J/\psi$, 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 $J/\psi D_s^* D_s$ coupling constant is $g_{J/\psi D^*_s D_s} = 4.30^{+0.42}_{-0.37}\text{GeV}^{-1}$.