Configuration-space-Faddeev born approximations

Alternative definitions of the Born approximation and the distorted-wave Born approximation within the framework of the configuration-space Faddeev equations are explored. The most natural definition does not correspond to the Born approximation derived from the Schroedinger equation, even though the exact T-matrices for both formalisms are equivalent. The Schroedinger form is optimal, although it is shown that the differences are numerically unimportant. The DWBA corresponding to the Faddeev equations is not channel symmetric, although numerically this is unimportant for the p-d (Coulomb) case. The place in the partial-wave series beyond which the Born approximation can be effectively substituted for the exact result is briefly investigated for p-d and n-d scattering below breakup threshold. (author)