# Strong couplings and form factors of charmed mesons in holographic QCD

## TL;DR

This paper extends a holographic QCD model to include strange and charm quarks, successfully describing meson properties and interactions, and comparing results with lattice QCD and other approaches.

## Contribution

The authors develop a four-flavor holographic model that incorporates flavor symmetry breaking and computes meson couplings and form factors, extending previous two-flavor models.

## Key findings

- Reasonable description of meson masses and decay constants.
- Computed strong couplings and electromagnetic form factors.
- Results agree with lattice QCD and nonperturbative methods.

## Abstract

We extend the two-flavor hard-wall holographic model of Erlich, Katz, Son and Stephanov [Phys.\ Rev.\ Lett.\ {\bf 95}, 261602 (2005)] to four flavors to incorporate strange and charm quarks. The model incorporates chiral and flavor symmetry breaking and provides a reasonable description of masses and weak decay constants of a variety of scalar, pseudoscalar, vector and axial-vector strange and charmed mesons. In particular, we examine flavor symmetry breaking in the strong couplings of the $\rho$ meson to the charmed $D$ and $D^{*}$ mesons. We also compute electromagnetic form factors of the $\pi$, $\rho$, $K$, $K^*$, $D$ and $D^*$ mesons. We compare our results for the $D$ and $D^*$ mesons with lattice QCD data and other nonperturbative approaches.