Calculation of multichannel reactions in the four-nucleon system above   breakup threshold
  Exact four-body equations of Alt, Grassberger and Sandhas are solved for neutron-${}^3\mathrm{He}$ and proton-${}^3\mathrm{H}$ scattering in the energy regime above the four-nucleon breakup threshold. Cross sections and spin observables for elastic, transfer, charge-exchange, and breakup reactions are calculated using realistic nucleon-nucleon interaction models, including the one with effective many-nucleon forces due to explicit $\Delta$-isobar excitation. The experimental data are described reasonably well with only few exceptions such as vector analyzing powers. 
A. Deltuva and A. C. Fonseca
nucl-th cond-mat.quant-gas nucl-ex physics.atom-ph