Quarkonium production from fixed-target to collider energies: status and prospects

Quarkonia are considered among the most important probes of the Quark-Gluon Plasma (QGP) since the very beginning of studies with ultrarelativistic heavy-ion collisions. Their rich spectroscopy, with various states having binding energies spanning more than one order of magnitude, offers a specific tool for the QGP characterization. In this seminar, after a brief introduction, I will concentrate on studies of the psi(2S) resonance, that were first carried out at fixed-target energies (SPS) and more recently at the LHC. I will report on the available results, mainly from the NA50 experiment at the SPS and, much more recently, from the ALICE experiment. Some details on the analysis procedures and the related difficulties will be given, and the overall physics picture that can be extracted from the available data will be discussed. The role played by results from small collision systems, in particular at LHC energy, will also be examined. Finally, prospects for future measurements will be shortly presented.