Charge-symmetry breaking in then−pinteraction

A simplified formalism of evaluating the isospin-violating amplitude of the neutron-proton scattering in terms of the bar phase shifts is presented. The singlet-triplet mixing angles are evaluated for the following effects: electromagnetic contributions, $\omega {\rho }^0$ mixing, and neutron-proton mass difference effect in the charged $\pi$ and $\rho$ one-meson exchanges. The possible difference in the polarization of neutrons and protons is estimated for four lab energies: 200, 325, 500, and 750 MeV.