Strong two-meson decays of light and charmed vector mesons

We calculate the strong decay couplings for $\rho \to \pi \pi$, $\phi \to KK$, $K^{\ast }\to K\pi$ and $D^{\ast }\to D\pi$ in a unified and consistent approach based on the impulse approximation, nonperturbative solutions of the quark-gap equation and the Poincaré invariant Bethe-Salpeter amplitudes of vector and pseudoscalar mesons. In particular, we obtain the coupling $g_{D^{\ast }\text{\hspace{0.17em}⁣}D\pi }=17.24_{-2.30}^{+3.06}$ in very good agreement with the experimental value by CLEO, which corresponds to a strong effective coupling between heavy vector and pseudoscalar mesons to the pion of $\widehat{g}=0.58_{-0.08}^{+0.10}$.