Reaction p-barp--> Lambda -bar Lambda in the meson-exchange picture.

Abstract

A study of the strangeness production process {ital {bar p}p}{r arrow}{bar {Lambda}}{Lambda} at threshold and intermediate energies has been performed doing a full coupled-channel ({ital {bar p}p},{bar {Lambda}}{Lambda}) calculation. The elastic part of the {ital {bar p}p} and {bar {Lambda}}{Lambda} interactions has been derived from a one-boson-exchange version of the Bonn {ital NN} potential and a corresponding extension to the hyperon-nucleon case whereas the annihilation part is taken into account by introducing suitable optical potentials. The transition interaction between {ital {bar p}p} and {bar {Lambda}}{Lambda} is based on {ital K}- and {ital K}{sup *}-meson exchange. A reasonably good description of empirical cross sections as well as polarization data is achieved. It is demonstrated that the results are quite sensitive even to short-range modifications of the channel interactions. We also compare our model with other approaches and suggest a new experiment which would be able to check the very different predictions of the meson-exchange and constituent quark model, respectively.