Associated-quarkonium production

We discuss the growing interest to measure associated-quarkonium production in a number of channels at the LHC.Whereas back-to-back production of quarkonium + isolated photon provides a unique way to extract gluon TMDs, observables such as quarkonium + W /Z can be of great help to better understand the quarkonium production mechanism as well as to shed light on double-parton scatterings.Along these lines, we also argue that quarkonium-pair production is a potentially rich source of information which only has started to be harvested.Finally, we discuss the relevance of studying the production of quarkonium + heavy-quark, as e.g.J/ψ + charm and ϒ + non-prompt J/ψ.