Differential cross section forn-pelastic scattering in the angular region 50°<θ*<180° at 459 MeV

The differential cross section for n-p elastic scattering at 459 MeV in the c.m. angular region 50°<${\mathrm{\theta }}^{\mathrm{*}}$<180° has been measured with high statistical precision and good relative accuracy. The uncertainty in the absolute normalization (based on the simultaneously measured yield of deuterons from the np→d${\mathrm{\pi }}^0$ reaction) was initially estimated to be ∼7%. The results agree well with back-angle data obtained independently at LAMPF but less well with results from Saclay and the Princeton-Pennsylvania Accelerator and, except for a normalization difference of 10%, are fairly well represented by a phase-shift fit. The pole-extrapolation method of Chew was used to extract the pion-nucleon coupling constant ${\mathit{f}}^2$ from the back-angle portion of the data. The value obtained, ${\mathit{f}}^2$=0.069, is somewhat smaller than the values 0.0735–0.0790 obtained from analyses of pion-nucleon scattering, tending to confirm the need for an upward renormalization of the angular distribution by ∼10%.