Polarisation-dependent studies of exclusive J/ψ production in hadron-hadron and lepton-hadron interactions

We studied polarisation-dependent exclusive J/ψ production in ultraperipheral heavy-ion collisions at RHIC and LHC energies and in $eA$ collisions at EIC energies, in the framework of color glass condensate effective theory. The azimuthal averaged J/ψ production cross section measured by STAR and ALICE is accurately described by our calculation. We further predict significant cos 2φ azimuthal asymmetries both in UPCs and in $eA$ collisions, which are attributed to the linearly polarized photon, the double-slit interference effect in photonuclear reactions, and the final state soft photon radiation effect. This study may provide further information on limiting gluon transverse spatial distribution inside large nuclei.