Even at moderate energy machines, there is a regime where hard pion
electroproduction proceeds by a perturbatively calculable process. The process,
we claim, is not the leading twist fragmentation one but rather a higher twist
process that produces kinematically isolated pions. Semiexclusive data may
teach us more about parton distribution functions of the target and the pion
distribution amplitude. In addition, there is a connection to generalized
parton distribution calculations of exclusive processes in that the
perturbative kernel is the same.Comment: 8 pages, 9 figures, Written version of invited talk by CEC at the
Second International Symposium on the Gerasimov-Drell-Hearn sum rule and the
spin structure of the nucleon (GDH2002), Genoa, Italy, 3--6 July 2002, and of
talk by CEC under the title ``Hard Pion Electroproduction at Medium
Energies'' at the XVI International Conference on Particles and Nuclei
(PANIC02), Osaka, Japan, 30 September--4 October 2002 [WM-02-111;
JLAB-THY-02-62
