Joint ECFA-NuPECC-APPEC Workshop “Synergies between the EIC and the LHC”

Transverse momentum dependent parton distribution functions (TMDs) encode essential information on the transverse motion of partons inside nucleons, as well as their spin-orbit correlations. In this talk I will show how, by looking at the azimuthal asymmetries in the inclusive production of pairs of vector quarkonia ($J/\psi$, $\psi(2S)$, $\Upsilon$ mesons), one can probe different TMDs. In particular, quark and antiquark TMDs could be accessed in pion-proton scattering at the COMPASS and AMBER experiments at CERN, where the contributions of gluons is negligible. The impact of the present and future fixed-target experiments at the LHC (SMOG, LHCspin) on this kind of studies will be discussed as well.