PRODUCTION OF 3 PIONS IN PP ANNIHILATIONS AT REST

We present results on annihilations of antiprotons at rest in hydrogen to the π+π-π0 final state. The analysis leads to the following general conclusions: 1. (a) The reaction pp → π+π-πo accounts for (6.9 ± 0.4)% of the total number of annihilations. 2. (b) 84% of the reaction proceeds from the 3S1 initial state which, by spin, parity and isospin conservation, leads to odd angular momenta between two pions in the final state. We find that this channel is dominated by the ρ{variant}π production. 3. (c) 16% of the reaction proceeds from the 1So initial state. Although the 1So state may lead to odd and even angular momenta between two pions, we do not find any P-wave dipion contribution, while 4% of the reaction is attributed to foπo production. 4. (d) A satisfactory interpretation of our data requires, besides the simple final state interaction model, the introduction of a direct three-pion production amplitude. 5. (e) 12% of the reaction is attributed to S-wave dipion production. We fail to find any dynamical structure in this channel and give only upper limits for σ and ε production. © 1968.