Study of the reaction π+p → ϱ0 Δ++(1236) at 16 GeV/c

The reaction π+p → ϱ0Δ++(1236) at 16 GeV/c has been studied. Cross section, differential cross section, single and joint spin-density matrix elements are given. Correlations between the ϱ0 and Δ++(1236) decay distributions are observed. Unnatural spin-parity exchanges, mainly observed at small t' values, dominate the ϱ0 Δ++(1236) production. The natural exchange contributions are only (7 ± 2)% and become as important as the unnatural exchanges beyond t' = 0.3 GeV2. Contributions to Δ++(1236) helicity 32 states do not exceed 20% of the total ϱ0 Δ++(1236) cross section and are mainly due to unnatural exchanges.