Inclusive $\Lambda$ production in proton-proton collisions at 3.5 GeV

The inclusive production of Λ hyperons in proton-proton collisions at s=3.18GeV was measured with HADES at the GSI Helmholtzzentrum fur Schwerionenforschung in Darmstadt. The experimental data are compared to a data-based model for individual exclusive Λ production channels in the same reaction. The contributions of intermediate resonances such as Σ(1385), Δ++, or N* are considered in detail. In particular, the result of a partial-wave analysis accounts for the abundant pK+Λ final state. Model and data show a reasonable agreement at midrapidities, while a difference is found for larger rapidities. A total Λ production cross section in p+p collisions at s=3.18GeV of σ(p+p→Λ+X)=207.3±1.3−7.3+6.0(stat.)±8.4(syst.)−0.5+0.4(model.)μb is found.