The representation theory of the symmetry group of lattice fermions as a basis for kinematics in lattice QCD

The symmetry group of staggered lattice fermions is discussed as a discrete subgroup of the symmetry group of the Dirac-Kähler equation. For the representation theory of this group, G. Mackey's generalization of E.P. Wigner's procedure for the construction of unitary representations of groups with normal subgroups is used. A complete classification of these irreducible representations by “momentum stars”, “flavour orbits” and “reduced spins” is given.