Exploring the hidden charm of quark-gluon plasma

Quark–gluon plasma is an extremely hot and dense state of matter in which the elementary constituents—quarks and gluons—are not confined inside composite particles called hadrons, as they are in the protons and neutrons that make up the nuclei of atoms. Thought to have existed in the early universe, this special phase of matter can be recreated at the Large Hadron Collider (LHC) in collisions between lead nuclei.