PROBING THE PION SEA WITH PI-D DRELL-YAN PROCESSES

Pion sea quark distributions are relatively poorly determined. We show that combinations of pi(+) and pi(-) Drell-Yan measurements on deuter ium allow the pion sea distribution to be extracted. The contribution from the sea of the pion is comparable with that from its valence quar ks and hence the experiment should be quite sensitive to the fraction of the pion momentum carried by the sea. We estimate the charge symmet ry violating [CSV] contributions to these processes, and show that pio n sea distributions could still be extracted in the presence of CSV te rms.