Spinors and supersymmetry in four-dimensional euclidean space

Spinors in four-dimensional Euclidean space are treated using the decomposition of the Euclidean space SO(4) symmetry group into SU(2) x SU(2). Both 2- and 4-spinor representations of this SO(4) symmetry group are shown to differ significantly From the corresponding spinor representations of the SO(3, 1) symmetry group in Minkowski space. The simplest self conjugate supersymmetry algebra allowed in four-dimensional Euclidean space is demonstrated to be an N = 2 supersymmetry algebra which resembles the N = 2 supersymmetry algebra in four-dimensional Minkowski space. The differences between the two supersymmetry algebras gives rise to different representations;in particular an analysis of the Clifford algebra structure shows that the momentum invariant is bounded above by the central charges in 4dE. while in 4dM the central charges bound the momentum invariant from below. Dimensional reduction of the N = 1 SUSY algebra in six-dimensional Minkowski space (6dM) to 4dE reproduces our SUSY algebra in 4dE. This dimensional reduction can be used to introduce additional generators into the SUSY algebra in 4dE. Well known interpolating maps are used to relate the N = 2 SUSY algebra in 4dE derived in this paper to the N = 2 SUSY algebra in 4dM. The nature of the spinors in 4dE allows us to write an axially gauge invariant model which is shown to be both Hermitian and anomaly-free. No equivalent model exists in 4dM. Useful formulae in 4dE are collected together in two appendixes. (C) 2001 Academic Press.