Light baryon production in binary annihilation reactions at rest

We report the study of light baryon production in two-prong annihilation reactions due to antiprotons stopping in gaseous deuterium and detected by the OBELIX spectrometer (LEAR, CERN). A clear signal of the Δ(1232) production in binary reactions was found in both annihilation channels: p d→π − Δ + (Δ + →π 0 p) and p d→π 0 Δ 0 (Δ 0 →π − p) . The annihilation probabilities for these reactions turned out to be Y=(1.01±0.08)×10−5 and Y=(1.12±0.20)×10−5, respectively. In addition, the annihilation probability for the prototype Pontecorvo reaction p d→π − p was measured with the best world statistics: Y=(1.46±0.08)×10−5.