Tests of factorization in strong-interaction few-body problems

A frequently employed approximation in momentum integrals in few-body problems is to assume that the integrand is sharply peaked in regions where the bound particles have low internal momentum. If justified, this allows one to remove portions of the integrand and evaluate them at their peak-value momentum points. In the extreme case, the only remaining term in the integral is the momentum wave function, whose integral corresponds to a position-space wave function evaluated at zero interparticle separation. The validity of this approximation is examined for systems of two and three strongly interacting particles.