2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191962We present the most accurate and complete data set for the analyzing power Ay(theta) in neutron-proton scattering. The experimental data were corrected for the effects of multiple scattering, both in the center detector and in the neutron detectors. The final data at En = 12.0 MeV deviate considerably from the predictions of nucleon-nucleon phase-shift analyses and potential models. The impact of the new data on the value of the charged pion-nucleon coupling constant is discussed in a model study.Six pages, four figures, one table, to be published in Physics Letters BNuclear Experimenttext