SOLITON QUANTIZATION AND INTERNAL SYMMETRY

We apply the method of collective coordinate quantization to a model o f solitons in two spacetime dimensions with a global U(1) symmetry. In particular we consider the dynamics of the charged states associated with rotational excitations of the soliton in the internal space and t heir interactions with the quanta of the background field (mesons). By solving a system of coupled saddle-point equations we effectively sum all tree graphs contributing to the one-point Green's function of the meson field in the background of a rotating soliton. We find that the resulting one-point function evaluated between soliton states of defi nite U(1) charge exhibits a pole on the meson mass shell and we extrac t the corresponding S-matrix element for the decay of an excited state via the emission of a single meson using the standard Lehmann-Symanzi k-Zimmermann reduction formula. This S-matrix element has a natural in terpretation in terms of an effective Lagrangian for the charged solit on states with an explicit Yukawa coupling to the meson field. We calc ulate the leading-order semiclassical decay width of the excited solit on states and discuss the consequences of these results for the hadron ic decay of the DELTA resonance in the Skyrme model.