$D^*D\rho$ and $B^*B\rho$ strong couplings in light-cone sum rules.

We present an improved calculation of the strong coupling constants $g_{D^*D\rho}$ and $g_{B^*B\rho}$ in light-cone sum rules including the one-loop QCD corrections of leading power with $\rho$ meson distribution amplitudes. We further compute the subleading-power corrections from two-particle and three-particle higher-twist contributions at leading order up to twist-4 accuracy. The next-to leading order corrections to leading power contribution offset the subleading-power corrections to some extend numerically, and our numerical results are consistent with previous works from sum rules. The comparisons between our results and the existing model-dependent estimations are also made.