Semileptonic Decays of Heavy Vector Mesons in Hard-Wall AdS/QCD with $N_f=5$

We present a systematic study of semileptonic decays of heavy vector mesons within the Hard-Wall AdS/QCD framework. Semileptonic decays provide a clean environment for testing the Standard Model because the leptonic current is well understood, while the hadronic part is encoded in transition form factors that reflect non-perturbative QCD dynamics. The processes under consideration include: $\psi \to D^{\ast -}(D^{-}){\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $D^{\ast 0}\to {\pi }^{-}{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $D_s^{\ast +}\to K^0{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $D^{\ast 0}\to {\rho }^{-}{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $B_c^{\ast +}\to B^{\ast 0}{\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $B_c^{\ast +}\to \psi {\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $B^{\ast -}\to D^{\ast 0}{\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$, $B^{\ast 0}\to D^{\ast +}(D^{+}){\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$, $B_s^{\ast 0}\to D_s^{\ast +}(D_s^{+}){\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$, $\psi \to D_s^{\ast -}(D_s^{-}){\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $D^{\ast 0}\to K^{\ast -}(K^{-}){\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}$, $B_c^{\ast -}\to D^{\ast 0}{\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$, ${\overline{B_s}}^{\ast 0}\to K^{\ast +}{\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$, and ${\bar{B}}^{\ast 0}\to {\rho }^{+}{\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}$. These decays correspond to four different quark-level transitions: $c\to d$, $b\to c$, $c\to s$, and $b\to u$, allowing us to explore a broad range of flavor dynamics.\ Using the Hard-Wall AdS/QCD model, we compute the relevant transition form factors as functions of the momentum transfer $q^2$. The framework provides analytic expressions for meson wave functions and decay constants, which serve as inputs for the form-factor calculations. From these form factors, we evaluate the differential and integrated branching ratios for each decay mode. Where possible, we compare our predictions with results obtained from other non-perturbative approaches.