INFN What Next: Ultra-relativistic Heavy-Ion Collisions

This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale diFisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phasediagram of strongly-interacting matter and of the Quark–Gluon Plasma (QGP) deconfined state will proceed,in the next 10–15 years, along two directions: the high-energy regime at RHIC and at the LHC, and thelow-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the presentand future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phaseof high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity,there is a growing interest in a possible future experiment at the SPS, which would target the search forthe onset of deconfinement using dimuon measurements. On a longer timescale, the community looks withinterest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ionbeams and on the Future Circular Collider.