Vector Supersymmetry: Casimir operators and contraction from OSp(3,2|2)

We study some algebraic properties of the vector supersymmetry (VSUSY) algebra, a graded extension of the four-dimensional Poincare algebra with two odd generators, a vector and a scalar, and two central charges. The anticommutator between the two odd generators gives the four-momentum operator, from which the name vector supersymmetry. We construct the Casimir operators for this algebra and we show how both algebra and Casimirs can be derived by contraction from the simple orthosymplectic algebra OSp(3,2|2). In particular, we construct the analogue of superspin for vector supersymmetry and we show that, due to the algebraic structure of the Casimirs, the multiplets are either doublets of spin (s,s+1) or two spin 1/2 states. Finally, we identify an odd operator, which is an invariant in a subclass of representations where a BPS-like algebraic relation between the mass and the values of the central charges is satisfied.

Space-time Vector Supersymmetry and Massive Spinning Particle

We construct the action of a relativistic spinning particle from a non-linear realization of a space-time odd vector extension of the Poincare group. For particular values of the parameters appearing in the lagrangian the model has a gauge world-line supersymmetry.{As a consequence of this local symmetry there are BPS solutions in the model preserving 1/5 of the supersymmetries.} A supersymmetric invariant quantization produces two decoupled 4d Dirac equations.