The antinucleon–nucleon interaction at low energy: Annihilation dynamics

Abstract

The general properties of antiproton-proton annihilation at rest are presented, with special focus on the two-meson final states. The data exhibit remarkable dynamical selection rules: some allowed annihilation modes are suppressed by one order of magnitude with respect to modes of comparable phase-space. Various phenomenological analyses are reviewed, based on microscopic quark dynamics or symmetry considerations. The role of initial-and final-state interaction is also examined.

Origin of the structures observed ine+e−annihilation into multipion states around thep¯pthreshold

“…1. Note that the lowest "data" point is not from a measurement but deduced from the branching ratios [18] and the total annihilation cross section [22] as discussed in the preceding paragraph.…”

Nuclear effects in protonium formation low-energy three-body reaction: p̄ + (pμ)1s→ (p̄p)α+μ−: Strong p̄–p interaction in p̄ + (pμ)1s

“…At the same time the main contribution from s-and p-states (polarization) is taken into account. A direct inclusion of the strongp−p interaction [14,15] would be a very interesting future investigation in the framework of the three-body reaction (3).…”

“…The last circumstance is responsible for interesting resonance and quasi-bound states in Pn [11]. Therefore, Pn represents a very useful tool to study, for example, the anti-nucleon−nucleon (NN) interaction potential [12,13] and annihilation processes [14,15]. Additionally, as we already mentioned, the interplay between Coulomb and nuclear forces plays a significant role in thep and p quantum dynamics [16].…”

Status of X(1835) and pp¯ Interaction from Chiral Symmetry

“…The annihilation effect in NN is known to be an indispensable part, see e.g., Refs. [26,27]. Without considering annihilations, one can not get a realistic NN potenial, and then all their conclusions are rather qualitative.…”