Graded GL(1/1) BRST symmetry in covariant quantization of supersymmetric chiral bosons and heterotic strings

In this paper the authors present a covariant path integral quantization of supersymmetric chiral bosons (leftons and rightons). an infinite set of auxiliary scalar superfields are introduced to convert the second-class chiral constraint into first-class ones. The authors' gauge-fixed action has an extended BRST symmetry described by the graded algebra GL(I | I). a regularization respecting this symmetry is proposed to deal with the contributions of the infinite towers of auxiliary fields and associated ghosts and is verified to lead to the desired partition function. The authors apply their formulation to give a covariant quantization of the heterotic-type NSR strings, and show that (super)conformal anomalies from all unphysical degrees of freedom are cancelled, even in noncritical dimensions. The authors' treatment does not suffer form Siegel gauge anomaly, because of the use of linear chiral constraints