Neutron-Proton Scattering in the Region 0-5 Mev

The theoretical cross section for scattering of neutrons by protons has been calculated on the basis of a pure central Yukawa potential with the same range in ${}_{}{}^1{}_{}{}^{}S$ and ${}_{}{}^3{}_{}{}^{}S$ states, corresponding to meson mass 200 and 300, respectively. The results indicate that the best over-all fit with most recent scattering experiments would be obtained with a meson mass of roughly 350 $m_e$. Allowing different ranges in singlet and triplet states and making use of the deuteron binding energy, we found a "triplet mass" of 290 and a "singlet mass" of about 380.