Energy Dependence of Multi-Pion Production in High-Energy Nucleus-Nucleus Collisions

Exclusive ${\ensuremath{\pi}}^{\ensuremath{-}}$ and charged-particle production in collisions of Ar+KCl is studied at incident energies from 0.4 to 1.8 GeV/u. Complete disintegration of both nuclei is observed. The correlation between ${\ensuremath{\pi}}^{\ensuremath{-}}$ and total charge multiplicity shows no islands of anomalous pion production. For constant numbers of proton participants the ${\ensuremath{\pi}}^{\ensuremath{-}}$ multiplicity distributions are Poissons. For central collisions $〈{n}_{{\ensuremath{\pi}}^{\ensuremath{-}}}〉$ increases smoothly and to first order linearly with the c.m. energy. Disagreement with the firestreak model is found.