Renormalization of a higher conservation law in the massive Thirring model

The classical massive Thirring model in two dimensional space time has an infinite number of independent nontrivial conserved currents. A Backlund transformation associated with the set of conserved currents has been found and Polyakov (1975) has observed that provided the conservation laws of the model are respected by the quantum corrections to the classical approximations the corresponding five matrices are pure phases (i.e. no particle production or nontrivial multiparticle scattering). The renormalization of the first nontrivial conserved classical current in the massive Thirring model with dimension and tensor structure higher than those of the energy- momentum tensor is analysed. (6 refs).