The Drell-Yan measurement at COMPASS-II

The Drell-Yan process can be used to access Transverse Momentum Dependent Parton Distribu- tion Functions (TMD PDFs), such as the Sivers and the Boer-Mulders functions, as well as the transversity function providing complementary information to what is known from Semi Inclu- sive Deep Inelastic Scattering (SIDIS) data. The COMPASS experiment offers the possibility to study single polarized Drell-Yan processes making use of its large accep- tance spectrometer and its unique transversely polarised proton target. Moreover a fundamental test of the factorization theorem in the non-perturbative QCD can be performed, by verifying the sign change of the T-odd Boer-Mulders and Sivers functions depending if they are accessed via SIDIS or Drell-Yan process. As the start of the Drell-Yan program at COMPASS is approaching, foreseen in late 2014, the spectrometer has been updated to fulfill the needs of this measurement