Manifest chiral symmetry preservation in the 1/N-expanded SU(N) Thirring model

By utilizing manifestly chiral-invariant auxiliary field operators, it is demonstrated that continuous chiral symmetry is preserved explicitly in the 1/N expansion of 2-dimensional theories whose fermions have a Gross-Neveu type of potential. The effective lagrangian derived in the 1/N limit describes a massless scalar field whose derivative coupling to the fermions vanishes as N → infinite, and decoupled massiv scalar field. (orig.)