Soft-pion emission in high-energy heavy-ion collisions

Abstract

We revive Heisenberg's approach to multiparticle production in the context of soft-pion emission in heavy-ion collisions. Adopting appropriate boundary conditions, we find a general analytic solution of the classical equations of motion for the nonlinear $\ensuremath{\sigma}$ model (for soft pions this model is an approximation to QCD). The solution is used to discuss various features of soft pion production in nuclear collisions.