Pion structure function from low-p T hadron production

The recombination model for low-p _T inclusive reactions is extended to the meson fragmentation region. Some basic issues in the model are rrexamined, and the differences between the proton and pion initiated reactions are stressed. By applying the model to theπ ⁺ p→K ⁺ X reaction, the fast valence quark distribution in the pion is extracted. Our best fit to the data yieldsF _q ^π (x)～(1?x)^0.8±0.2 for largex.