Proton-induced pre-equilibrium composite-particle emission

The reaction mechanism of proton-induced composite particle pre-equilibrium emission as an intrinsic part a statistical multistep process was confirmed long ago. Nevertheless, until fairly recently it was still not clear how pickup and knockout processes compete in the multistep sequence to produce a composite ejectiles. An overview of results and conclusions based on recent (p,alpha) studies at incident energies from 65 to 200 MeV are presented and evaluated. It is shown how analyzing power is a valuable observable for unravelling the details of the reaction mechanism. Future avenues of investigation are discussed.