EXACT SCATTERING IN THE SU(N) SUPERSYMMETRIC PRINCIPAL CHIRAL MODEL

The complete spectrum of states in the supersymmetric principal chiral model based on SU(n) is conjectured, and an exact factorizable S-matr ix is proposed to describe scattering amongst these states, The SU(n)( L) x SU(n)(R) symmetry of the Lagrangian is manifest in the S-matrix c onstruction. The supersymmetries, on the other hand, are incorporated in the guise of spin-1/2 charges acting on a set of RSOS kinks associa ted with su(n) at level n. To test the proposed S-matrix, calculations of the change in the ground-state energy in the presence of a couplin g to a background charge are carried out. The results derived from the Lagrangian using perturbation theory and from the S-matrix using the TEA are found to be in complete agreement for a variety of background charges which pick out, in turn, the highest weight states in each of the fundamental representations of SU(n). In particular, these methods rule out the possibility of additional CDD factors in the S-matrix. C omparison of the expressions found for the free-energy also yields an exact result for the mass gap in these models: m/Lambda<(MS)over bar> = (n/pi) sin(pi/n). (C) 1997 Elsevier Science B.V.