Differential cross section for n-p elastic scattering in the angular range $60°<{\theta }^{*}<180\mathrm{}°$ at 801.9 MeV

The differential cross section for n-p elastic scattering at 801.9 MeV has been measured with high statistical precision and good relative accuracy over the angular range $60°<{\theta }^{*}<180\mathrm{}°$. The absolute normalization is based on the simultaneously observed yield of deuterons from the $\mathrm{np}\to \mathrm{d}{\pi }^0$ reaction and is good to 7%. A nearly monoenergetic neutron beam, produced by proton bombardment of a liquid-deuterium target, was directed through a liquid-hydrogen target. The angle, velocity, and momentum of charged particles ejected from the target were measured in a magnetic spectrometer equipped with multiwire proportional chambers and timing scintillators. The results are in good agreement with earlier Saclay and LAMPF data and include an angular region not covered before. The pole-extrapolation method of Chew was used to extract a value $f^2=0.075\mathrm{}\pm 0.005$ for the pion-nucleon coupling constant which is in agreement with accepted values, thus providing evidence for the accuracy of the shape and normalization of the angular distribution.