The reactions $pp\to p\hat{I}›K^{+}$ and $pp\to p\hat{I}{\pounds }^0{K}^{+}$ near their thresholds

Abstract

The reactions $pp\to p\hat{I}›K^{+}$ and $pp\to p\hat{I}{\pounds }^0{K}^{+}$ are studied near their thresholds. The strangeness production process is described by the $\ddot{I}€$- and $K$ exchange mechanisms. Effects from the final state interaction in the hyperon-nucleon system are taken into account rigorously. It is found that the $\hat{I}›$ production is dominated by $K$ exchange whereas $K$- as well as $\ddot{I}€$ exchange play an important role for the $\hat{I}{\pounds }^0$ case. It is shown that the experimentally observed strong suppression of $\hat{I}{\pounds }^0$ production compared to $\hat{I}›$ production at the same excess energy can be explained by a destructive interference between $\ddot{I}€$ and $K$ exchange in the reaction $pp\to p\hat{I}{\pounds }^0{K}^{+}$. Implications of such an interference on the reaction $pp\to n\hat{I}{\pounds }^{+}{K}^{+}$ are pointed out.

Revised version with corrected numerical results. The general conclusions remain unchanged