Pionic coupling constants of heavy mesons in the quark model

Abstract

We analyse pionic couplings of heavy mesons combining PCAC with the dispersion quark model to calculate the relevant transition form factors. Ground states and radial excitations are considered. For the ground state coupling constants the values $\hat g=0.5\pm0.02$ in the heavy quark limit, $g_{B^*B\pi}=40\pm 3$, $g_{D^*D\pi}=16\pm 2$ are obtained. A sizeable suppression of the coupling constants describing the pionic decays of the radial excitations is observed.