PROBING CHARGE-SYMMETRY-VIOLATING QUARK DISTRIBUTIONS IN SEMIINCLUSIVE LEPTOPRODUCTION OF HADRONS

Recent experiments by the HERMES group at DESY HERA are measuring semi -inclusive electroproduction of pions from deuterium. We point out tha t by comparing the production of pi(+) and pi(-) from an isoscalar tar get, it is possible, in principle, to measure charge symmetry violatio n in the valence quark distributions of the nucleons. It is also possi ble in the same experiments to obtain an independent measurement of th e quark fragmentation functions. We review the information which can b e deduced from such experiments and show the ''signature'' for charge symmetry violation in such experiments. Finally, we predict the magnit ude of the charge symmetry violation, from both the valence quark dist ributions and the pion fragmentation function, which might be expected in these experiments.