Matter–antimatter interactions involving antihydrogen

We review theoretical results for low-energy scattering of antihydrogen and atomic hydrogen and helium. Various inelastic channels, such as rearrangement and annihilation, as well as elastic scattering, are considered. In particular we give a progress report on our He–H¯ calculations and give preliminary results for the low-energy cross section for rearrangement into positronium and antiprotonic helium. As far as we are aware, this is the first time that these cross sections have been calculated.