DISORIENTED CHIRAL CONDENSATE FORMATION FROM TUBES OF HOT QUARK PLASMA

We investigate the time evolution of a system of quarks interacting wi th sigma and pion fields starting from an initial configuration consis ting of a tube of hot quark plasma undergoing a boost-invariant longit udinal expansion. We work within the framework of the linear sigma mod el using classical transport equations for the quarks coupled to the m ean-field equations for the meson fields. In certain cases we find str ong amplifications of any initial pion fields. For large-radius tubes, starting from quark densities that are very close to critical, we fin d that a disoriented chiral condensate can form in the center of the t ube. Eventually the collapse of the tube drives this state back to the true vacuum. This process converts the disoriented condensate, domina ted by long-wavelength pion modes, into a coherent excitation of the p ion field that includes significant components with transverse momenta of around 400 MeV. In contrast, for narrow tubes or larger initial te mperatures, amplification occurs only via the pion-laser-like mechanis m found previously for spherical systems. In addition, we find that ex plicit chiral symmetry breaking significantly suppresses the formation of disoriented condensates. [S0556-2821(98)03101-4].