A quark–gluon plasma (QGP) or quark soup[1] is a (possible) phase of quantum chromodynamics (QCD) which exists at extremely high temperature and/or density. This phase consists of asymptotically free quarks and gluons, which are several of the basic building blocks of matter. Experiments at CERN's Super Proton Synchrotron (SPS) first tried to create the QGP in the 1980s and 1990s: the results led CERN to announce indirect evidence for a "new state of matter"[2] in 2000. Current experiments (2011) at the Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) on Long Island (NY, USA) and at CERN's recent LHC collider near Geneva (Switzerland) are continuing this effort,[3][4] by smashing relativistically accelerated gold ions—at LHC, lead ions—into each other.

Although the results have yet to be independently verified as of February 2010, scientists at Brookhaven RHIC have tentatively claimed to have created a quark-gluon plasma with an approximate temperature of 4 trillion degrees Celsius.[4]

As already mentioned, three new experiments running on CERN's Large Hadron Collider (LHC), on the spectrometers ALICE,[5] ATLAS and CMS, will continue studying properties of QGP. Starting in November 2010, CERN temporarily ceased colliding protons, and began colliding lead Ions for the ALICE experiment. They were looking to create a QGP and were expected to stop December 6, colliding protons again in January.[6] A new record breaking temperature was set by the CERN group on August, 2012 in the ranges of 5.5 trillion degrees Celcius as claimed in their Nature PR. [7]

The strength of the color force means that unlike the gas-like plasma, quark-gluon plasma behaves as a near-ideal Fermi liquid, although research on flow characteristics is ongoing.[8]

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