Theoretical cross sections for keV antiprotons

Abstract

Partial and total close-coupled semiclassical (impact parameter) cross sections and total classical Monte-Carlo cross sections for interactions in $$\bar p + Ps$$ and $$\bar p$$ , p+H collisions are computed in the intermediate keV range for antiprotons, $$\bar p$$ , up to 100 keV lab. Total cross sections for antihydrogen, $$\bar H$$ , formation are found to be large, 10−20×10−16 cm2 in a wider energy range than was anticipated earlier, up to some 20 keV lab. New estimates of cross sections for ionisation of atomic hydrogen by antiproton impact are reported for the low-energy range 1–30 keV lab where they are 10−20×10−17 cm2, being much larger than the corresponding cross sections for ionisation of hydrogen by proton impact. Data for excitation of H by $$\bar p$$ impact is also presented.