AFFINE (TWO-LOOP) WZNW MODEL, REDUCTION AND SPONTANEOUS BREAKDOWN OF CONFORMAL SYMMETRY

A large theory—the affine (two-loop) WZNW theory, which is universal in the sense that (at least classically) conformal and integrable models may be considered as its various reductions, has been proposed in our recent papers with Bonora and Martellini. In this letter we study a different Hamiltonian reduction (named as type III reduction in the text) of the affine (two-loop) WZNW model and discuss the integrability property of the reduced model. By a BRST analysis, we elaborate on a previously introduced idea regarding integrable systems as spontaneously conformal-symmetry-broken versions of CFTs.