I will present recent developments in 4N scattering research by addressing mixed isospin T=0 and 1 reactions initiated by p+3H, n+3He or d+d collisions.
In the energy regime where two, three- and four-cluster channels are open these processes resemble a typical nuclear reaction where elastic, charge exchange, transfer, and breakup scattering take place simultaneously. The results are obtained using the momentum-space transition operator framework. Recent advances in three-body nuclear reactions involving composite nuclei will be discussed as well.