Mass Splitting of Staggered Fermion and $SO(2D)$ Clifford Algebra
  We present a new method to introduce rotationally invariant terms in staggered fermions which is based on an $SO(2D)$ Clifford algebra formulation, where $D$ means the number of space-time dimensions. We have four candidates for improved mass terms that can split the degenerate mass of staggered fermions. Among them, we analyze three types of combinations and find only one case that can identify with the light single Dirac mode. 
M. Hatakeyama, H. Sawanaka, H. So