ALICE studies the primordial quark-gluon matter produced when atomic nuclei collides at ultra-relativistic energies.
ALICE (A Large Ion Collider Experiment) is an experiment at the 27-km circumference Large Hadron Collider (LHC) at CERN. It studies the emergent properties of quarks and gluons at extreme energy densities produced when two atomic nuclei, such as lead-lead, are collided.
QCD is the theory that describes how quark and gluons interact. Normally, quarks and gluons are confined inside hadrons such as the proton and the neutron that make up the atomic nuclei. However, QCD predicts that, at sufficiently high temperatures and/or densities, there will be a transition from hadronic matter, to a plasma of deconfined quarks and gluons - the quark-gluon plasma (QGP). This transition occurred in the early universe micro-seconds after the Big Bang and the goal of the experiment at CERN is to reproduce and study the properties of this primordial quark-gluon matter.
The Lund group is the only Swedish group that studies the QGP experimentally and has been active in ALICE since the 90s. ALICE is the only experiment at the LHC that is optimized for the study of heavy-ion collisions, which is where the QGP is traditionally investigated. ALICE extends a long tradition of experiments done at lower collision energy both at BNL in the US and at CERN, where the Lund group has also been active.