NP SCATTERING MEASUREMENTS AT 162 MEV AND THE PI-NN COUPLING-CONSTANT

The differential np scattering cross section has been measured at 162 MeV in the angular range theta(c.m.) = 72 degrees-180 degrees, using t he neutron beam facility at The Svedberg Laboratory in Uppsala. Specia l attention was paid to the absolute normalization of the data. In the angular range 150 degrees-180 degrees, the data are steeper than thos e of most previous measurements and predictions from energy-dependent partial-wave analyses or nucleon-nucleon potentials. At 180 degrees, t he difference is of the order of 10-15%, an important change since thi s cross section is considered as a primary standard. It has also conse quences for fundamental physics. Moreover, a value of the charged pi N N coupling constant, g(pi+/-)(2) = 14.52 +/- 0.26 (f(pi+/-)(2) = 0.080 3 +/- 0.0014), is deduced from the data, using a novel extrapolation m ethod. This is in good agreement with the classical text book value, b ut higher than those determined in recent partial-wave analyses of the nucleon-nucleon data base.