QCD, the theory of strongly interacting matter, predics that, above a critical energy density, hadrons, the constituents or normal nuclear matter, decompose into a plasma of quarks and gluons, the Quark Gluon Plasma, QGP. Such a state existed shortly after the Big Bang and may exist as well in the neutron stars. Colliding heavy ions at extreme energies is the only way to study QGP on Earth.
The phase diagram of nuclear matter
History of the Universe poster picture from CERN QGP press release


A. Andronic
Last modified: Tue Jan 30 18:58:53 CET 2007