A Review of N̄N Annihilation Potentials at Low Energies and the Shifts and Widths of p̄-Nucleus Atomic Bound States
Over the last ten years much progress has been made in deriving a theoretical NN potential that is capable of explaining NN scattering in detail1. The long range part of this potential (r ≳ 0.8 fm) is based on π +2π + ω exchange with the short range phenomenological core being adjusted to fit NN phase shifts in low partial waves. This knowledge of the NN potential then gives, through the G-parity transformation, a model for the long range part of the N̄N potential. However, this is not the whole story, since it does not take into account the N̄N annihilation. Usually this is described by means of an additional phenomenological complex potential — taken to be purely imaginary in early attempts2, but nowadays also with a real component3. Even though these complex potentials are introduced to simulate the effect of inelastic channels, their form is taken to be very simple, often not even exhibiting such expected features as the energy dependence from threshold behaviours at the opening of inelastic channels. Exceptions to this last objection are the works of ref.4,12 in which the complex annihilation potential has the threshold behaviour of an “average” inelastic channel giving 3–4 pions.
KeywordsCouple Channel Inelastic Channel Rearrangement Model Inelastic Integrate Cross Section Individual Partial Wave
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