ON DUALITY AND REFLECTION FACTORS FOR THE SINH-GORDON MODEL WITH A BOUNDARY

The sinh-Gordon model with integrable boundary conditions is considere d in low order perturbation theory. It is pointed out that results obt ained by Ghoshal for the sine-Gordon breather reflection factors sugge st an interesting dual relationship between models with different boun dary conditions. GhoshaI's formula for the lightest breather is checke d perturbatively to O(beta(2)) in the special set of cases in which th e phi--> -phi symmetry is maintained. It is noted that the parametriza tion of the boundary potential which is natural for the semiclassical approximation also provides a good parametrization at the ''free-fermi on'' point.