The reactions pp→ pΛK+ and pp→ pΣ0K+ near their thresholds

Abstract

The reactions pp→ pΛK + and pp→ pΣ 0 K + are studied near their thresholds. The strangeness production process is described by the π- and K exchange mechanisms. Effects from the final state interaction in the hyperon-nucleon system are taken into account rigorously. The Λ production turns out to be dominated by K exchange whereas K- as well as π exchange play an important role for the Σ 0 case. It is shown that the experimentally observed strong suppression of Σ 0 production compared to Λ production at the same excess energy can be explained by a destructive interference between π and K exchange in the reaction pp→ pΣ 0 K +. Implications of such an interference on the reaction pp→ nΣ + K + are pointed out.