  We examine the validity of the notion of the coherent state for pions and the
quantum scattering effect in the final state of pion emission. When the number
of particles is large, the effect caused by the small but finite mass
difference between the neutral and charged pions can add up substantially in
the quantum evolution of an initially coherent state. As a result, the states
with quite different numbers of neutral or charged pions are essentially
incoherent. The importance of the quantum scattering in the final-state isospin
charge distribution of a disoriented chiral condensate (DCC) is investigated.
We find that the scattering effect significantly reduces the spectacular
Centauro and anti-Centauro events. The deformation of a charge distribution
$dP/df$ predicted by the classical field theory is significant only for a DCC
with the size of 10 fm or more.
