How parametric resonance mechanism follows quench mechanism in disorientedchiral condensate

We show how parametric resonance mechanism follows quench mechanism in the classical linear sigma model. The parametric resonance amplifies long wavel ength modes of the pion for more than 10 fm/c. The shifting from the quench mechanism to the parametric resonance mechanism is described by a time dep endent quantity. After the quench mechanism is over, that quantity has an o scillating part, which causes the parametric resonance. Since its frequency is 2m(pi) (m(pi) : pion mass), very long wavelength modes such as k = 40 M eV of the pion are amplified by the parametric resonance. (C) 2001 Publishe d by Elsevier Science B.V.