Theoretical prediction of a new state of matter, the "quark-gluon plasma" (also called "quark matter")

This contribution is a reproduction by the editors of the original transparencies. It discusses the following: Constitution of hadronic matter according to quantum chromodynamics (QCD), a non-abelian gauge theory based on SU$_{3}$ (colour quantum numbers); Spinor fields $\rightarrow$ quarks, SU$_{3}$ triplets, 5 (6?) ''flavours''; and gauge fields $\rightarrow$ gluons, SU$_{3}$ octets, no further internal quantum numbers; confinement property: hadronic systems in the vacuum form SU$_{3}$ singlets (''colourless''). Examples: baryon = $(qqq)_{singlet'}$, meson = ($q\bar{q})_{singlet'}$ where $q, \bar{q}$ may be ''dressed'' by a ''sea'' of $q\bar{q}$ pairs and gluons. A nucleus is also a SU$_{3}$ singlet, containing 3A quarks and perhaps more ($q\bar{q}$) pairs. The $q, \bar{q}$ distribution in nuclei is not the one in nucleons folded with the Fermi distribution (EMC effect).