SUPERPARTICLE WITH EXTENDED WORLDLINE SUPERSYMMETRY

We consider the superparticle action of Sorokin, Tkach and Volkov, which has both spacetime and extended worldline supersymmetry. We give a full off-shell description of the D = 4, 6 (N = 2, 4 worldline) cases in the presence of supergravity and gauge background fields. The actions have the form of the geometric relations defining the chiral D = 4 and harmonic-analytic D = 6 bases in curved superspace, multiplied by Lagrange multipliers. Thus the form of the action is determined by the prepotentials of conformal supergravity and super-Yang-Mills theory.