Polarized Drell-Yan studies at COMPASS

The COMPASS experiment at CERN will soon start a new series of measurements using a pion beam and a transversely polarized target. The study of the polarized Drell-Yan process will provide an insight of the transverse momentum dependent parton distribution functions (TMDs), which is complementary to their extraction from semi-inclusive deep inelastic scattering (SIDIS), previously measured in COMPASS. The sign change of Sivers and Boer-Mulders TMDs, when accessed from SIDIS or Drell-Yan, is predicted by theory. Its experimental observation is considered an essential test of the TMD approach. The experimental aspects of the Drell-Yan measurement in COMPASS are discussed. The set-up optimization, driven by the results of several beam tests are presented, as well as the expected event rates and statistical errors of the azimuthal asymmetries