Production and decay mechanism of the B meson and the ωπ system in π+p interactions at 5 GeV/c

The production and decay properties of the B meson are studied in the reaction π+p→ωπ+p at 5 GeV/c, where a cross section of 98±16 μb is found for the final state pB+. The production angular distribution of the B+ shows a forward peak, a possible shoulder at t′∼0.25 GeV2, and a small backward peak. The most likely spin-parity assignment for the B is found to be 1+, and the D-wave fraction in the B decay is ∼ 11%. The differential cross section and density matrix elements of the B+ suggest a dominant ω-exchange contribution. The suppression of A2 exchange is also apparent in a study of the reaction π+p→B0Δ++. We obtain for tpΔ′<1 GeV2 an estimated cross section of 15±12 μb for B0Δ++ production, which is about 5 times smaller than that of pB+ at the same t′ region. The reaction ππ→πω, extrapolated to the pion pole, is found to yield near the πω threshold cross sections smaller than previously expected.