MARGINAL DEFORMATIONS OF WZNW AND COSET MODELS FROM O(D, D) TRANSFORMATIONS

We show that the O(2,2) transformation of the SU(2) WZNW model gives rise to marginal deformation of this model by the operator integral d2zJ(z)J(z)BAR where J, JBAR are U(1) currents in the Cartan subalgebra. Generalization of this result to other WZNW theories is discussed. We also consider the O(3,3) transformation of the product of an SU(2) WZNW model and a gauged SU(2) WZNW model. The three-parameter set of models obtained after the transformation is shown to be the result of first deforming the product of two SU(2) WZNW theories by marginal operators of the form SIGMA(i,j=1)2 C(ij)J(i)J(j)BAR, and then gauging an appropriate U(1) subgroup of the theory. Our analysis leads to a general conjecture that O(d, d) transformations of any WZNW model correspond to marginal deformation of the WZNW theory by an appropriate combination of left and right moving cur-rents belonging to the Cartan subalgebra; and O(d, d) transformations of a gauged WZNW model can be identified to the gauged version of such marginally deformed WZNW models.