# Coupling constants calculation of charmed meson with kaon from QCD sum rules

## TL;DR

This paper calculates the strong coupling constants of specific charmed meson-kaon vertices using three-point QCD sum rules, providing new estimates for the basic g parameter in heavy quark effective theory.

## Contribution

It introduces a calculation of coupling constants for several charmed meson-kaon vertices using QCD sum rules, including the first estimation of the g parameter consistent with existing predictions.

## Key findings

- Calculated coupling constants for multiple vertices.
- Estimated the g parameter as 0.24±0.09.
- Results agree with lower limits of previous predictions.

## Abstract

In this research, the strong coupling constants of the $D^*D_s^*K$, $D_1D_{s1}K$, $D^*D_sK$ and $D_1D_{s0}^*K$ vertices are evaluated, using the three-point QCD sum rules. In order to calculate the coupling constant of each vertex, either the kaon or the charmed meson is considered as the off-shell particle. The basic $g$ parameter, in the heavy quark effective theory, is related to the coupling constants of $D^*D_s^*K$ and $D^*D_sK$. Our obtained value for $g$ parameter is $0.24\pm 0.09$, which is in good agreement with the lower limits of the other existing predictions.