npscattering measurements at 162 MeV and theπNNcoupling constant

The differential $\mathrm{np}$ scattering cross section has been measured at 162 MeV in the angular range ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=72\mathrm{}°-180°$, using the neutron beam facility at The Svedberg Laboratory in Uppsala. Special attention was paid to the absolute normalization of the data. In the angular range $150°-180°$, the data are steeper than those of most previous measurements and predictions from energy-dependent partial-wave analyses or nucleon-nucleon potentials. At $180°$, the difference is of the order of 10–15%, an important change since this cross section is considered as a primary standard. It has also consequences for fundamental physics. Moreover, a value of the charged $\pi \mathrm{NN}$ coupling constant, $g_{{\pi }^{\pm }}^2=14.52\mathrm{}\pm 0.26\hspace{0.5em}{(f}_{{\pi }^{\pm }}^2=0.0803\mathrm{}\pm 0.0014)$, is deduced from the data, using a novel extrapolation method. This is in good agreement with the classical text book value, but higher than those determined in recent partial-wave analyses of the nucleon-nucleon data base.