Coupled-channel effects in hadron-hadron correlation functions

Abstract

Two-particle momentum correlation functions as measured in heavy ion collisions or in high-energetic proton-proton collisions are studied. Special emphasis is put on systems like $\Lambda\Lambda$ or $K^-p$ where effects from the coupling to other channels could be relevant. In both cases other channels open at relatively low momenta or are already open at the reaction threshold. To have a solid basis, realistic coupled-channel interactions for $\Lambda\Lambda-\Xi N-\Lambda\Sigma-\Sigma\Sigma$ and $\pi\Lambda-\pi\Sigma-\bar KN$ are utilized in the actual calculations. It is found that the opening of the $\Xi N$ channel leaves a trace in the $\Lambda\Lambda$ correlation function that could be detectable in experiments. Should the proposed $H$-dibaryon be located close to or below the $\Xi N$ it will have a very pronounced effect. The presence of open channels in systems like $\Xi^- p$ or $K^-p$ does influence the correlation functions significantly at low momenta and will certainly complicate any dedicated analysis.