Normalization of neutron-proton differential cross sections

Abstract

The np differential cross section below 350 MeV neutron laboratory energy is studied using the energy-dependent Nijmegen partial-wave analysis PWA93. We analyze in detail three experiments, performed at LAMPF, at TRIUMF, and at the TSL facility in Uppsala. The issue of normalization of $np$ cross sections is discussed, where we distinguish between measured and calculated normalizations. This analysis leads to improved treatments of the LAMPF and TRIUMF data over PWA93. It is shown that the LAMPF and TRIUMF data at Tlab = 212 MeV are in good agreement with PWA93, that the LAMPF data at Tlab = 162 MeV is also in good agreement with PWA93, but that the Uppsala data at 162 MeV is in strong disagreement with PWA93. The reason for the disagreement is, almost certainly, a systematic flaw in the slope of the Uppsala data.