Phase-shift analysis ofNNscattering below 160 MeV: Indication for a strong tensor force

A new phase-shift analysis of NN scattering in the energy range 15–160 MeV is presented. The analysis is based on the carefully reviewed world pp+np data, including recent results for higher-order spin observables in n-p scattering. The latter are essential to determine the mixing parameter ${\mathrm{\varepsilon }}_1$ which is directly related to the isoscalar tensor force. ${\mathrm{\varepsilon }}_1$ displays a high trend, in agreement with recent analyses above 140 MeV, and is only reproduced by potential models with a strong tensor force. The prediction of the full Bonn potential is too low by 20% for energies above 40 MeV. All other I=0 phase shifts show agreement with potential models; in particular, the notorious problem with ${}_{}{}^1{}_{}{}^{}$ ${\mathit{P}}_1$ around 50 MeV has disappeared. Around 25 MeV a ten parameter fit based purely on np data agrees with the corresponding fit to the pp data and reveals no indication of anomalous charge independence breaking.