QCD matter
（重定向自Quagma）
![Particle debris trajectories from one of the first lead-ion collisions with the LHC, as recorded by the ALICE detector.](/Images/godic/202502/05/Alicelead30232.jpg")
![Conjectured form of the phase diagram of QCD matter, with temperature as ordinate (in mega-electron volts) and quark chemical potential as abscissa.[7]](/Images/godic/202502/05/QCD_phase_diagram0232.png")
![](/Images/godic/202502/05/Phase_change_-_en.svg0232.png")
Quark matter or QCD matter refers to any of a number of theorized phases of matter whose degrees of freedom include quarks and gluons. These theoretical phases would occur at extremely high temperatures and densities, billions of times higher than can be produced in equilibrium in laboratories. Under such extreme conditions, the familiar structure of matter, where the basic constituents are nuclei (consisting of nucleons which are bound states of quarks) and electrons, is disrupted. In quark matter it is more appropriate to treat the quarks themselves as the basic degrees of freedom.