On the geometrization of the electro-magnetic interaction for a spinning   particle
  We outline that, in a Kaluza-Klein framework, not only the electro-magnetic field can be geometrized, but also the dynamics of a charged spinning particle can be inferred from the motion in a 5-dimensional space-time. This result is achieved by the dimensional splitting of Papapetrou equations and by proper identifications of 4-dimensional quantities. 
Francesco Cianfrani, Irene Milillo, Giovanni Montani