Can nearby resonances enhance D0−D̄0

We study the contributions of resonances to D0−D̄0 mixing. Both QQ̄ and hybrid QQ̄G states are considered. Assuming reasonable values for the resonance parameters, we find relatively sizeable individual contributions to both ΔmD and ΔΓD. We derive a variant of the GIM cancellation mechanism for the resonance amplitudes and show that broken SU(3) can allow for appreciable residual effects. Additional input from meson spectroscopy and lattice gauge simulations will be needed to improve the accuracy of these predictions.