Probing the pion sea with π-D Drell-Yan processes

Pion sea quark distributions are relatively poorly determined. We show combinations of π+ and π− Drell-Yan measurements on deuterium allow the pion sea distribution to be extracted. The contribution from the sea of the pion is comparable with that from its valence quarks and hence the experiment should be quite sensitive to the fraction of the pion momentum carried by the sea. We estimate the charge symmetry violating [CSV] contributions to these processes, and show that pion sea distributions could still be extracted in the presence of CSV terms.