Heavy Meson Dynamics in a QCD Relativistic Potential Model

We use a QCD relativistic potential model to compute the strong coupling constant $g$ appearing in the effective Lagrangian which describes the interaction of $0^-$ and $1^-$ $\bar q Q$ states with soft pions in the limit $m_Q \to \infty$. We compare our results with other approaches; in particular, in the non relativistic limit, we are able to reproduce the constituent quark model result: $g=1$, while the inclusion of relativistic effects due to the light quark gives $g={1 \over 3}$, in agreement with QCD sum rules. We also estimate heavy meson radiative decay rates, with results in agreement with available experimental data.