Reactions with leading hadrons in meson-proton interactions at 250 GeV/ $c$

Inelastic final states with one or two leading hadrons are studied in 7r+p and K+p interactions at 250 GeV/c. In reactions with two leading hadrons, the dependence of the average charge multiplicity of associ ated pions on their effective mass is essentially consis tent with that observed in pp and 7 7 -collisions, but differs from that obtained in e+e"-annihilation. The multiplicity and (semi)inclusive characteristics of the 7r+-induced non- diffractive reactions are compared to predictions of current versions of the FRITIOF fragmentation model. We show that the hard-like sub-processes, essentially responsible for the production of leading hadrons with relatively large trans verse momentum as well as for the relatively large multi plicity of associated pions, are not properly treated in the model.