Spinning-particle model for the Dirac equation and the relativistic   Zitterbewegung
  We construct the relativistic particle model without Grassmann variables which meets the following requirements. A) Canonical quantization of the model implies the Dirac equation. B) The variable which experiences {\it Zitterbewegung}, represents a gauge non-invariant variable in our model. Hence our particle does not experiences the undesirable {\it Zitterbewegung}. C) In the nonrelativistic limit spin is described by three-vector, as it could be expected. 
A. A. Deriglazov
hep-th math-ph math.MP quant-ph