Motion of coloured particles in solitons of the O 3 non-linear model

We propose a consistent expression for the relativistic quadri-force referring to the classical interaction between a coloured particle and a scalar field multiplete. General aspects of the resultant equations of motion are discussed as well as a specialisation to the case of a SU 2 particle in the presence of a soliton configuration of the non-linear O 3 model with unit topological charge. Analytical studies regarding the stability and asymptotic behaviour of this system are made and extended to the case of arbitrary topological charge. Since the non-linear O 3 model describes an isotropic ferromagnet, we also investigate a possible physical interpretation of such a system.