Abstract :
This process is discussed quantum-mechanically, using a partial wave expansion for the spectator nucleon and applying selection rules for transitions from specific p̄d atomic states. A selection rule for the p̄d atomic s-state with J=32 plays an essential role; the transition is forbidden for 1S0 annihilation occurring with a spectator nucleon in an s-state in the overall centre of mass system. This leads to strong P-state annihilation to C=+1 final states, in agreement with experiment. In contrast, annihilation to C=−1 final states is mostly through 3S1, and little P-state annihilation is predicted. For atomic p-states, S-state p̄N annihilation is predicted to dominate over P-state annihilation for all p̄d spin states and spectator momenta <0.1 GeV/c.
