TWISTORS, N = 8 SUPERCONFORMAL INVARIANCE, AND THE GREEN-SCHWARZ SUPERSTRING

After replacing the space-time variables of the d-dimensional Green-Schwarz superstring lagrangian with twistor variables (d = 3, 4, 6, or 10), the first-class constraints are separated out from the second-class constraints. These first-class constraints are shown to form an N = d - 2 super-Virasoro algebra, out of which can be constructed a manifestly super-Poincare invariant BRST charge with only two levels of reducibility. When d = 10, all potential quantum anomalies vanish and the BRST charge is nilpotent.