In 2015 and 2018 the COMPASS experiment at CERN measured muon-pair production in the Drell-Yan (DY) and J/Psi channels using a 190 GeV π − beam impinging on a transversely polarized NH 3 and unpolarized nuclear targets ( 27 Al, 184 W). Apart from the absolute cross-section measurements for both processes, COMPASS studies also the target spin (in)dependent azimuthal asymmetries in both channels. Assuming the valence quark-antiquark annihilation to be the main production mechanism, one can

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... et the azimuthal asymmetries in terms of convolutions of pion and proton Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs). The TMD PDFs are universal QCD objects providing a mapping of parton densities in 3D momentum space. Recent results obtained by COMPASS for the DY and J/ψ channels will be discussed along with complementary semi-inclusive DIS (SIDIS) measurements and theoretical predictions.