Low-energy antinucleon-nucleus interaction revisited.

Annihilation cross sections of antiprotons and antineutrons on the proton between 50 and 400 MeV/c show Coulomb focusing below 200 MeV/c and almost no charge-dependence above 200 MeV/c. Similar comparisons for heavier targets are not possible for lack of overlap between nuclear targets studied with $\bar {p}$ and $\bar {n}$ beams. Interpolating between $\bar {p}$-nucleus annihilation cross sections with the help of an optical potential to compare with $\bar {n}$-nucleus annihilation cross sections reveal unexpected features of Coulomb interactions in the latter. Direct comparisons between $\bar {n}$-nucleus and $\bar {p}$-nucleus annihilations at very low energies could be possible if $\bar {p}$ cross sections are measured on the same targets and at the same energies as the available cross sections for $\bar {n}$. Such measurements may be feasible in the foreseeable future. [ABSTRACT FROM AUTHOR]