Coulomb scattering in the presence of a low-frequency laser field

The cross section for scattering by a Coulomb potential, cut off at large distance, in the presence of a low-frequency laser field, is obtained as a power series in the laser frequency. The long-range nature of the potential introduces a change in the leading term (${\omega }^0$) as well as a new term proportional to $\omega \ln \omega$. It is also found that the Coulomb cutoff parameter can, under some circumstances, become an observable.