R-matrix description of particle energy spectra produced by low-energy ³H + ³H reactions

An R-matrix model for three-body final states is presented and applied to a recent measurement of the neutron energy spectrum from the ³H + ³H → 2n + α reaction. The calculation includes the n alpha and n n interactions in the final state, angular momentum conservation, antisymmetrization, and the interference between different channels. A good fit to the measured spectrum is obtained, where clear evidence for the ⁵He ground state is observed. The model is also used to predict the alpha-particle spectrum from ³H + ³H as well as particle spectra from ³He + ³He. The R-matrix approach presented here is very general, and can be adapted to a wide variety of problems with three-body final states