Ab initio description of and systems in optical models
Phys. Rev. C 113, 054003 – Published 18 May, 2026
DOI: https://doi.org/10.1103/c7s6-x4v9
Abstract
In the context of the ongoing PUMA experiment (CERN), which investigates antiproton annihilation on atomic nuclei, we study the energy shifts and widths of hydrogenic states in the and systems by performing ab initio calculations. The scattering lengths and scattering volumes are first determined by solving the Faddeev-Yakubovsky equations in configuration space. The level shifts and widths of the corresponding and hydrogen-like states are then obtained using the Trueman formula. A pronounced model dependence associated with the nucleon-antinucleon interaction is observed for certain states. Finally, annihilation densities are computed from the four-body wave functions. Comparison with the nuclear density distributions indicates that the antiproton-nucleus annihilation is predominantly peripheral.