A Way to Quark Matter: Possible Intermediate Stages

Abstract

Possibl~ intermediate stages from hadronic matter to the uniform quark matter are discussed. After a brief description on the energy properties of the uniform quark matter, two examples of intermediate phases are presented and discussed by taking reference to the uniform quark matter. The naive deconfinement phase transition to the uniform matter may occur at very high density, once we want to give a consistent description with low-lying hadron spectra. Then the concept of partial deconfinement turns out to play an important role, which suggests appearance of intermediate stages prior to the transition to the uniform quark matter. One possibility is a quark-layered structure with a specific spin-flavor order under the well-developed ;r 0 condensation which still persists between the quark matter slabs. The other is the matter consisting of H-particles in the flavor singlet and spinless six-quark state, which may stem from hyperonic matter and come into existence as a boson superfluid. In these stages some cooperative effects of hadronic and subhadronic degrees of freedom are appreciated.