Strange particle production in three- and four-body final states of 16 GeV/cπ±p reactions

Three- and four-body final states with strange particles are studied in π⁺p and π^?p interactions at 16 GeV/c. We present cross sections and investigate their energy dependence. Production mechanism, resonance production and quantum number transfer are discussed. Strong Y¹(1385) production is found in the reaction π⁺p → ΛK⁺π⁺, while the corresponding π^?p reaction is dominated by production of K¹(890). In the $\text{NK}\text{K}\text{π}$ channels, the K and $\text{K}$ are produced mainly at the same vertex, i.e. non-strangeness exchange ΔS = 0 is dominant (about 75% of the cases), whereas in the ΛKππ channels, the Λ and K are more frequently produced at opposite vertices, i.e. |ΔS| = 1 exchange is important (about 60% of the cases). Results on the polarization of the lambdas produced in the π⁺p reactions are given.