Soliton Solutions of the σ Model and the Disoriented Chiral Condensates

We derive travelling soliton solutions of the $\sigma$ model, relevant for the description of dynamics of pions, in the high-energy, heavy-ion collisions. These extended objects are analogs of Ne$\grave{e}$l and Bloch type defects in ferromagnetic systems and could possibly describe the disoriented chiral condensates. It is shown that these solutions are metastable and can naturally produce an asymmetry between $\pi^0 $ and $ \pi^+$, $\pi^- $ mesons in the soft-pion emissions from heavy-ion collisons.