The capture of slow antiprotons by noble gas atoms

The capture of slow antiprotons (impact energies less than 1.0 au) by the noble gases krypton and xenon is studied following the paper of Briggs at al [3], where the transient collision complex is treated as a diatomic molecule with the positively-charged atomic ion and antiproton as 'nuclei'. Estimates of the population of long-lived 'circular' states suggest that the probability of capture of antiprotons into such states is negligible. The capture cross sections for Kr and Xe are two orders of magnitude smaller than for He in agreement with experimental data [6].