REACTIONS WITH LEADING HADRONS IN MESON-PROTON INTERACTIONS AT 250 GEV C/

Inelastic final states with or two leading hadrons are studied in pi()p and 250 GeV/c. In reactions with two leading hadrons, the dependenc e of the average charge multiplicity of associated pions on their effe ctive mass is essentially consistent with that observed in (p) over ba r p and gamma gamma-collisions, but differs from that obtained in e(+) e(-)-annihilation. The multiplicity and (semi)inclusive characteristic s of the pi(+)-induced nondiffractive reactions are compared to predic tions of current versions of the FRITIOF fragmentation model. We show that the hard-like sub-processes, essentially responsible for the prod uction of leading hadrons with relatively large transverse momentum as well as for the relatively large multiplicity of associated pions, ar e not properly treated in the model.