(2-DIMENSIONAL MODELS OF RELATIVISTIC-PARTICLES WITH CURVATURE AND TORSION(1))

(2+1)-dimensional models of relativistic particles with the action dep ending arbitrarily on the world-trajectory curvature and torsion are i nvestigated. A special class of models, described by the action with a maximal symmetry allowing only spin internal degrees of freedom, is s ingled out. A classical analysis of the systems from this special clas s is carried out, and the quantization procedure for them is described . Within this class, tachyon-free models are pointed out and the syste ms having classical and quantum spectra with only massive spin states (whose number in the quantum case may be both finite and infinite) are considered as concrete examples of such models.