General Classical Solutions of Nonlinear $\sigma$-Model and Pion Charge Distribution of Disoriented Chiral Condensate

Abstract

We obtain the general analytic solutions of the nonlinear $\sigma$-model in $3+1$ dimensions as the candidates for the disoriented chiral condensate (DCC). The nonuniformly isospin-orientated solutions are shown to be related to the uniformly oriented ones through the chiral (axial) rotations. We discuss the pion charge distribution arising from these solutions. The distribution $dP/df=1/(2\sqrt{f})$ holds for the uniform solutions in general and the nonuniform solutions in the $1+1$ boost invariant case. For the nonuniform solution in $1+1$ without a boost-invariance and in higher dimensions, the distribution does not hold in the integrated form. However, it is applicable to the pions selected from a small segment in the momentum phase space. We suggest that the nonuniform DCC's may correspond to the mini-Centauro events.