The antinucleon–nucleon interaction at low energy: Annihilation dynamics

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.