Antineutron and antiproton nuclear interactions at very low energies

Experimental annihilation cross sections of antineutrons and antiprotons at very low energies are compared. Features of Coulomb focusing are observed for p¯ annihilation on protons. Direct comparisons for heavier targets are not straightforward due to lack of overlap between targets and energies of experimental results for p¯ and n¯. Nevertheless, the annihilation cross sections for n¯ on nuclei cannot be described by an optical potential that fits well all the available data on p¯ interactions with nuclei. Comparisons made with the help of this potential reveal in the n¯ data features similar to Coulomb focusing. Direct comparisons between n¯ and p¯ annihilations at very low energies would be possible when p¯ cross sections are measured on the same targets and at the same energies as the available cross sections for n¯. Such measurements may be possible in the foreseeable future.