LIP- Lisbon

on behalf of the COMPASS Collaboration The COMPASS experiment at CERN will start in October 2014 its Drell-Yan (DY) physics pro-gram. This is the first transversely polarized target Drell-Yan measurement ever performed, and it will provide new insight to the transverse momentum dependent (TMD) parton distribution functions. COMPASS measured already azimuthal single spin asymmetries in semi-inclusive DIS (SIDIS) processes, contributing in a decisive way to the present knowledge of the nucleon TMDs. The predicted sign change of the Sivers and Boer-Mulders TMDs when accessed from SIDIS or from DY processes will be verified by this new DY measurement