Charm and strangeness production in $\Sigma^{-}$ nucleus- interactions

We report on a study of the leading particle effect both in strange and charm final states. In the strange sector the inclusive cross sections for hyperon production in high-energy Sigma /sup -/, pi /sup -/ and neutron induced interactions were measured by the WA89 experiment at CERN. A strong leading effect for Xi /sup -/ produced by Sigma /sup -/ is observed. The influence of the target mass on the Xi /sup -/ cross section is explored by comparing reactions on copper and carbon nuclei. This constitutes the first measurement using three different projectiles and two different targets within the same experiment thus ensuring small systematic uncertainties. In the charm sector we studied the leading particle effect in D/sup -//D/sup +/, D /sub s//sup -//D/sub s//sup +/ and Lambda /sub c//sup +// Lambda /sub c//sup $/production in high energy Sigma /sup -/ interactions. The study of D/sub s//sup -//D/sub s//sup +/ production represents the first measurement of charm production with a leading strange quark. (5 refs).