Abstract

A U(1) gauge theory of a particle with arbitrary spin in three space-time dimensions is introduced. All the spin-dependent effects are a consequence of a direct coupling of the gauge field to the Chern-Simons field responsible for the shift in spin and statistics. Two approaches in relativistic quantum mechanics which take a spin-0 or a spin-1/2 state as starting point are shown to be equivalent and the result is that the total spin dependence reduces to a magnetic coupling with a gyromagnetic ratio g = 2 for any spin.