Microscopic calculation of the spin-dependent neutron scattering lengths on 3He

We report on the spin-dependent neutron scattering length on He from a microscopic calculation of p−H, n−He, and d−H scattering employing the Argonne v18 nucleon-nucleon potential with and without additional three-nucleon force. The results and that of a comprehensive R-matrix analysis are compared to a recent measurement. The overall agreement for the scattering lengths is quite good. The imaginary parts of the scattering lengths are very sensitive to the inclusion of three-nucleon forces, whereas the real parts are almost insensitive.