New superspaces/algebras for superparticles/strings
  We describe covariant derivatives with respect to the coordinates of the full superPoincar\'e group and dual coordinates, for Yang-Mills and supergravity. The derivatives have engineering dimension running from 0 to 2. Prepotentials appear as potentials for Lorentz derivatives (spin). Their role is clarified in a lightcone analysis, where they also act as compensating gauge parameters and Hertz potentials. Field strengths appear as potentials for dual-coordinate derivatives, until dimensional reduction. These generalizations extend the superstring's affine Lie algebra, and generalize gauge couplings for the superparticle. 
Warren Siegel
hep-th