Electroproduction of Charged Pions in the Quark-Fragmentation Region

This paper presents results of an experiment on hadron production in deep-inelastic electron scattering. Good agreement with the predictions of the quark-parton model is found. The Fragmentation functions for $u$ and $d$ quarks into pions are determined, and comparison is made with other deep-inelastic processes and with recent quark jet parametrizations.