T. Kunz

Partial wave analysis of the reaction p(3.5 GeV)+p → pK+Λ to search for the “ppK−” bound state

Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5GeV ) + p !pK + �. This reaction might contain information about the kaonic cluster ”ppK − ” via its decay into p�. Due to interference effects in our coherent description of the data, a hypothetical KNN (or, specifically ”ppK − ”) cluster signal must not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectra like p�. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a KNN cluster. At a confidence level of CLs=95% such a cluster can not contribute more than 2-12% to the total cross section with a pK + � final state, which translates into a production cross-section between 0.7 µb and 4.2 µb, respectively. The

Medium effects in proton-induced

We present the analysis of the inclusive K 0 production in p + p and p + Nb collisions measured with the HADES detector (GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt) at a beam kinetic energy of 3.5 GeV. Data are compared to the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model. The data suggest the presence of a repulsive momentum-dependent kaon potential as predicted by the chiral perturbation theory (ChPT). For the kaon at rest and at normal nuclear density, the ChPT potential amounts to ≈ 35 MeV. A detailed tuning of the kaon production cross sections implemented in the model has been carried out to reproduce the experimental data measured in p + p collisions. The uncertainties in the parameters of the model were examined with respect to the sensitivity of the experimental results from p + Nb collisions to the in-medium kaon potential.

K^{0}

An exclusive analysis of the 4-body final states

production at 3.5 GeV

\mathrm{\Lambda + p + \pi^{+} + K^{0}}