CRITICAL DIMENSION FOR THE SIEGEL ACTION WITH SUPERSYMMETRIC CHIRAL BOSONS ON GROUP MANIFOLDS
A classical covariant action which has the Siegel symmetry is constructed for supersymmetric chiral bosons in arbitrary curved space-time coupled to (1,0) world-sheet supergravity. The critical dimension is derived by two methods for such an action with leftons and rightons compactified on group manifolds GL × GR, i.e. by requiring either the closure of the Lorentz algebra in the uncompactified Minkowski space-time in the light-cone gauge approach or the cancellation of both the Siegel and conformal anomalies in the covariant approach. It turns out that the results in the two approaches generally do not agree with each other; in particular, some critical dimensions allowed in the light-cone gauge approach do not lead to anomaly cancellation in the covariant approach. This disagreement represents a pathological feature of Siegel's covariant approach (with usual gauge-fixing procedure) to supersymmetric chiral bosons.