the s-wave problem, by adopting an on-shell approximation for the T-matrix equation, we
derive analytical formulas which connect the Fourier transform V ̃ (k) of the interaction
potential to the s-wave phase shift. In this way we obtain explicit expressions of the low-
momentum parameters g ̃ 0 and g ̃ 2 of V ̃ (k)= g ̃ 0+ g ̃ 2 k 2+⋯ in terms of the s-wave
scattering length as and the s-wave effective range rs for D= 3, D= 2, and D= 1. Our results …