Backward scattering of low-energy antiprotons by highly charged and neutral uranium: Coulomb glory

TL;DR

This paper theoretically investigates the Coulomb glory effect in low-energy antiproton collisions with various uranium ions, revealing how electron screening influences the backward scattering cross section.

Contribution

It demonstrates how electron screening and vacuum polarization affect the Coulomb glory phenomenon in antiproton-uranium collisions across different charge states.

Findings

Coulomb glory effect is more pronounced with increased electron number.

Maximum differential cross section shifts to higher energies with more electrons.

Bare uranium exhibits a Coulomb glory due to vacuum polarization screening.

Abstract

Collisions of antiprotons with He-, Ne-, Ni-like, bare, and neutral uranium are studied theoretically for scattering angles close to 180$^{\circ}$ and antiproton energies with the interval 100 eV -- 10 keV. We investigate the Coulomb glory effect which is caused by a screening of the Coulomb potential of the nucleus and results in a prominent maximum of the differential cross section in the backward direction at some energies of the incident particle. We found that for larger numbers of electrons in the ion the effect becomes more pronounced and shifts to higher energies of the antiproton. On the other hand, a maximum of the differential cross section in the backward direction can also be found in the scattering of antiprotons on a bare uranium nucleus. The latter case can be regarded as a manifestation of the screening property of the vacuum-polarization potential in non-relativistic collisions of heavy particles.