The electromagnetic form factors in the $N_{f}=4$ holographic QCD

Abstract

In this study, we employ a modified soft-wall holographic model with four flavors to investigate the meson spectra, decay constants, electromagnetic form factors, and charge radius of various mesons. We obtain the spectra for vector, axial vector, and pseudoscalar mesons. Decay constants are calculated and compared with experimental and lattice QCD data. The pion and kaon electromagnetic form factors are compared with the experimental data, and a good agreement is achieved for the kaon at low $Q^{2}$. For the charmed mesons, the electromagnetic form factors of the $D$ and $D_{s}$ and electric form factors of the $D^{*}$ and $D_{s}^{*}$ are well consistent with the lattice QCD data. Moreover, the electric, magnetic, and quadrupole form factors are predicted for the $\rho$, $K^{*}$, $a_1$, $K_1$, $D_1$, and $D_{s1}$ mesons. Furthermore, the charge radius of the vector, axial vector, and pseudoscalars, including the strange and charmed mesons, are computed.