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A quark–gluon plasma (QGP) or quark soup is a state of matter in quantum chromodynamics (QCD) which is hypothesized to exist at extremely high temperature, density, or both temperature and density. This state is thought to consist of asymptotically free quarks and gluons, which are several of the basic building blocks of matter. It is believed that up to a few milliseconds after the Big Bang, known as the Quark epoch, the Universe was in a quark–gluon plasma state. In June 2015, an international team of physicists have produced quark-gluon plasma at the Large Hadron Collider by colliding protons with lead nuclei at high energy inside the supercollider’s Compact Muon Solenoid detector. They also discovered that this new state of matter behaves like a fluid.〔LHC creates liquid from Big Bang ()〕 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.〔(Quark-gluon plasma goes liquid - physicsworld.com )〕 In the quark matter phase diagram, QGP is placed in the high-temperature, high-density regime; whereas, ordinary matter is a cold and rarefied mixture of nuclei and vacuum, and the hypothetical quark stars would consist of relatively cold, but dense quark 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"〔(A New State of Matter - Experiments )〕 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 Large Hadron Collider near Geneva (Switzerland) are continuing this effort,〔(Relativistic Heavy Ion Collider, RHIC )〕〔 by colliding relativistically accelerated gold (at RHIC) or lead (at LHC) with each other or with protons. 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 (4×1012) degrees Kelvin.〔http://www.bnl.gov/rhic/news2/news.asp?a=1074&t=pr 'Perfect' Liquid Hot Enough to be Quark Soup〕 As already mentioned, three new experiments running on CERN's Large Hadron Collider (LHC), on the spectrometers ALICE,〔(Alice Experiment: Welcome to ALICE Portal )〕 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.〔(CERN Press Release November 4th 2010 )〕 A new record breaking temperature was set by ALICE: A Large Ion Collider Experiment at CERN on August, 2012 in the ranges of 5.5 trillion (5.5×1012) degrees Kelvin as claimed in their Nature PR.〔(Hot stuff: CERN physicists create record-breaking subatomic soup : Nature News Blog )〕 ==General introduction== Quark–gluon plasma is a state of matter in which the elementary particles that make up the hadrons of baryonic matter are freed of their strong attraction for one another under extremely high energy densities. These particles are the quarks and gluons that compose baryonic matter.〔(The Indian Lattice Gauge Theory Initiative )〕 In normal matter quarks are ''confined''; in the QGP quarks are ''deconfined''. In classical QCD quarks are the Fermionic components of mesons and baryons while the gluons are considered the Bosonic components of such particles. The gluons are the force carriers, or bosons, of the QCD color force, while the quarks by themselves are their Fermionic matter counterparts. Although the experimental high temperatures and densities predicted as producing a quark–gluon plasma have been realized in the laboratory, the resulting matter does ''not'' behave as a quasi-ideal state of free quarks and gluons, but, rather, as an almost perfect dense fluid. Actually, the fact that the quark–gluon plasma will not yet be "free" at temperatures realized at present accelerators was predicted in 1984 as a consequence of the remnant effects of confinement.〔.〕〔.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Quark–gluon plasma」の詳細全文を読む スポンサード リンク
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