IONIZATION IN COLLISIONS BETWEEN 30-1000 KEV ANTIPROTONS AND ATOMIC-HYDROGEN

Recently published data for impact of antiprotons in the energy range 30-1000 keV on atomic hydrogen are compared with analogous proton, ele ctron, and positron measurements, and it is found that the ionization cross sections of atomic hydrogen follow the same pattern as similar c ross sections obtained on He and H-2 targets, in accordance with the g eneral phenomenological description of single ionization that has deve loped over the last decade. Further comparisons are made with various recent and advanced theoretical calculations for antiproton ionization of atomic hydrogen. These theoretical results agree well with the dat a obtained, but for lower impact energies the different methods do not , despite the simplicity of the system, agree on predicting even the f orm of the cross section.