Disoriented chiral condensate dynamics in the(2+1)DO(3)model

Abstract

The dynamics of symmetry breaking after a quench is numerically simulated on a lattice for the (2+1)-dimensional $O(3)$ model. In addition to the standard sigma model with a temperature-dependent ${\ensuremath{\Phi}}^{4}$ potential the energy functional includes a four-derivative current-current coupling to stabilize the size of the emerging extended topological textures. The total winding number can be conserved by constraint. As a model for the chiral phase transition during the cooling phase after a hadronic collision this allows us to investigate the interference of ``baryon-antibaryon'' production with the developing disoriented aligned domains. The growth of angular correlations, condensate, and average orientation is studied in dependence of texture size, quench rate, and symmetry breaking. The classical dissipative dynamics determines the rate of energy emitted from the relaxing source for each component of the 3-vector field which provides a possible signature for the domains of disoriented chiral condensate (DCC). We find that the ``pions'' are emitted in two distinct pulses; for sufficiently small lattice size the second one carries the DCC signal, but it is strongly suppressed as compared to simultaneous ``sigma''-meson emission. We compare the resulting anomalies in the distributions of DCC pions with probabilities derived within the commonly used coherent state formalism.