to an estimate of star radius, combined with calculations of the equation of state relating the pressure and energy density of the star's core. The evidence was strongly suggestive but did not conclusively prove the existence of quark matter. See also Sources and further reading Aronson, S. and Ludlam, T.: "Hunting the quark gluon plasma", U.S. Dept. of Energy (2005) Letessier, Jean: Hadrons and quark-gluon plasma, Cambridge monographs on particle physics, nuclear physics, and cosmology (Vol. 18), Cambridge University Press (2002) References External links Virtual Journal on QCD Matter RHIC finds Exotic Antimatter Quantum chromodynamics Phases of matter Plasma physics Unsolved problems in physics