Theory of the Reactionn+d→n+n+p

We calculate the proton energy spectrum at various angles for the process $n+d\to n+n+p$ at 14.4-MeV incident-neutron laboratory energy, using our exact three-body theory with separable, $S$-wave, spin-dependent, two-body forces. The major features of the experimental data are reproduced, but not the precise magnitudes. The integral equations we solve are quite singular and we find it necessary to deform the integration path. This involves the careful treatment of some branch points. Our results are not good enough to resolve the problem of the neutron-neutron scattering length, but by comparing Watson theory with our exact calculations we show that Watson theory is inadequate in this problem.