Neutron–Proton Scattering Length Data Extracted from the $${n+{}^{2}}\mathbf{H}{\to n+n+p}$$ Reaction at $${E_{n}=5}$$ MeV

The $$nd$$ breakup reaction at an energy of 5 MeV was studied on the RADEX neutron channel of the Institute for Nuclear Research of the Russian Academy of Sciences. As a result of comparing the experimental data with the simulation results, the energy of the virtual $${}^{1}S_{0}$$ $$np$$ state $$E_{np}=40\pm 2$$ keV and the corresponding singlet $$np$$ scattering length $$a_{np}={-}30.9\pm 0.8$$ fm were extracted. It was assumed that the obtained $$a_{np}$$ value, together with the data of other experiments on the study of $$nd$$ and $$dd$$ breakup reactions at different energies, are subject to the influence of $$3N$$ forces. The work was carried out as part of a series of studies on internucleon interactions at low energies.