Inclusive {\Lambda} production in proton-proton collisions at 3.5 GeV

TL;DR

This paper measures inclusive { extLambda} hyperon production in proton-proton collisions at 3.18 GeV, compares data with a detailed model including resonances, and reports a total production cross section with reasonable agreement at mid rapidities.

Contribution

It provides the first detailed measurement and modeling of inclusive { extLambda} production at this energy, including resonance contributions and partial wave analysis.

Findings

Total { extLambda} production cross section is 207.3 μb.

Model and data agree at mid rapidities but differ at larger rapidities.

Resonance contributions significantly affect { extLambda} production.

Abstract

The inclusive production of {\Lambda} hyperons in proton-proton collisions at $\sqrt{s}$ = 3.18 GeV was measured with HADES at the GSI Helmholtzzentrum f\"ur Schwerionenforschung in Darmstadt. The experimental data are compared to a data-based model for individual exclusive {\Lambda} production channels in the same reaction. The contributions of intermediate resonances such as {\Sigma}(1385), {\Delta}++ or N* are considered in detail. In particular, the result of a partial wave analysis is accounted for the abundant pK$^+${\Lambda} final state. Model and data show a reasonable agreement at mid rapidities, while a difference is found for larger rapidities. A total {\Lambda} production cross section in p+p collisions at $\sqrt{s}$ = 3.18 GeV of {\sigma}(pp $\to$ {\Lambda} + X) = 207.3 $\pm$ 1.3 +6.0 -7.3 (stat.) $\pm$ 8.4 (syst.) +0.4 -0.5 (model) {\mu}b is found.