MASSIVE SUPERPARTICLE IN D=2+1 AND SIGMA-MODEL SOLITONS

We show that the gauge-fixed N = 2, d=2+l massive superparticle has N = 4 woridline supersymmetry that is partially broken down to N = 2 by the central charge in the supersymmetry algebra. The fact that this model has partial breaking of supersymmetry implies that it is the leading term in the effective action for the solitons of N = 2 supersymmetric, 2 + 1-dimensional sigma models that saturate a Bogomol’nyi bound. Invariant actions can be obtained using the method of nonlinear realizations applied to the N = 2 super-Poincare group in three dimensions. By explicitly including the central charge in the algebra, the superparticle action appears as a Wess-Zumino-type term. We also construct a supersymmetric extension of a term quadratic in the extrinsic curvature of the woridline, which corresponds to the first correction in the effective action of the soliton. © 1990 IOP Publishing Ltd.