On rescattering effects in the reaction $\pi^- d \to \pi^- d$

We discuss rescattering corrections to the impulse approximation for the processes $\pi^- d\to\pi^- d$ and $\gamma d\to\pi^0 d$. It is shown that the rescattering effects (RE) give non-negligible contribution to the real part of these amplitudes. At the same time the contributions from the imaginary parts of impulse and rescattering corrections drastically cancel each other. This cancellation means that the processes $\pi^- d\to \pi^0 nn$ and $\gamma d\to \pi^+ nn / \pi^- pp$ are strongly suppressed near threshold as required by the Pauli principle.