Alternative formulations of first quantized covariant string action

Abstract

In the covariant formulation of the first quantized action for a string propagating in Minkowski space it is natural to introduce a field (called dualbein) which is a worldsheet vector as well as a spacetime vector. The dualbein is a logical generalization of the zweibein. In terms of the dualbein field we construct new covariant actions for the bosonic strings and the superstrings. The casev of massless superparticles is also discussed.