Nonequilibrium pion dynamics near the critical point in a constituent quark model

D. Boyanovsky , H. J. de Vega (1) , S. -Y. Wang

1 LPTHE - Laboratoire de Physique Théorique et Hautes Energies

We study static and dynamical critical phenomena of chiral symmetry breaking in a two-flavor Nambu--Jona-Lasinio constituent quark model. We obtain the low-energy effective action for scalar and pseudoscalar degrees of freedom to lowest order in quark loops and to quadratic order in the meson fluctuations around the mean field. The \emph{static} limit of critical phenomena is shown to be described by a Ginzburg-Landau effective action including \emph{spatial} gradients. Hence \emph{static} critical phenomena is described by the universality class of the O(4) Heisenberg ferromagnet. \emph{Dynamical} critical phenomena is studied by obtaining the equations of motion for pion fluctuations. We find that for $T

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]

D. Boyanovsky, H. J. de Vega, S. -Y. Wang. Nonequilibrium pion dynamics near the critical point in a constituent quark model. Nuclear Physics A, 2004, 741, pp.323. ⟨hal-00102073⟩