$D_{(s)}-$ mesons semileptonic form factors in the 4-flavor holographic QCD

Abstract

We investigate semileptonic form factors of $D_{(s)}$ meson from a modified soft-wall 4-flavor holographic model. The model successfully reproduces the masses and decay constants of various mesons, including $\rho$, $K^{\ast }$, $D^{\ast }$, $D_s^{\ast }$, $a_1$, $K_1$, $f_1$, $D_1$,$D_{s1}$, $\pi$, $K$, $\eta$, $D$, and $D_s$. Moreover, we study the semileptonic decay processes $D^{+}\to (\pi ,K,\eta )l^{+}{\nu }_l$ and $D_s^{+}\to (K,\eta )l^{+}{\nu }_l$, associated with the vector meson exchange, as well as $D_{(s)}^{+}\to K^{}{l}^{+}{\nu }_l$, associated with the vector and axial vector meson exchange. The form factors $f_{+}(q^2)$ for $D\to \pi$ and $D_{(s)}\to K$ decays agree excellently with experimental and lattice data, outperforming other theoretical approaches. The $f_{+}(q^2)$ form factor for $D^{+}\to \eta$ is compatible with experimental data, while a slight discrepancy is observed for $D_s^{+}\to \eta$ at large $q^2$. Additionally, we predict the vector form factors $V(q^2)$ and $A_1(q^2)$ for $D\to K^{}$ and $D_s\to K^{}$ decays, respectively. The results agree well with other approaches and lattice data at maximum recoil ($q^2=0$).

Comments: arXiv admin note: text overlap with arXiv:2308.14975