Marcia Quaresma
LIP
The first worldwide dedicated measurement of the polarised Drell-Yan process took place in 2015 in COMPASS experiment at CERN. The CERN SPS 190 GeV/c negative pion beam and a transversely polarised ammonia target were used. The first results are now available, after 16 months since the data taking ended. The measured azimuthal spin asymmetries in the produced dimuons will be presented. These are related with Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs), which allow to describe the nucleon dynamics. The TMD PDFs can also be accessed through other processes and in particular in COMPASS in Semi Inclusive Deep Inelastic Scattering (SIDIS). This complementarity allows unique tests of fundamental QCD (restricted) universality predictions that will be discussed in the presentation.
