Analytic study of disoriented chiral condensate
  Evolution of disoriented chiral condenstates is studied with the classical sigma model in 3+1 dimensions. By smoothly connecting a chiral symmetric solution of the formation period to a solution of the decay period, we obtain a complete spacetime evolution of the pion field for a simple and physically interesting source. The formation process is discussed quantitatively from the viewpoint of the axial-vector isospin conservation. 
M. Suzuki