Multi-cut forced impulse method single-ionization cross sections for slow antiprotons on helium

We present multi-cut forced impulse method cross sections for the single ionization of helium by antiprotons in the energy range 12-200 keV amu-1. Eight segmented time intervals, bracketed by collapse onto fully correlated states, are needed to establish convergence in the effects of intermediate dynamic correlation. At low energies the theoretical cross sections fail to reproduce experiments. We point out that a similar situation obtains for the antiproton-hydrogen system. (author)