Electron capture to the continuum by proton and positron impact

We describe recent experimental triple-differential cross sections of ionization by the impact of both protons and positrons by means of a single, kinematically exact theory. This model incorporates all the interactions in the final state on an equal footing and keeps an exact account of the three-body kinematics. We show that these provisions make it possible to evaluate any multiple-differential cross section for any given mass configuration, and analyse how it changes with the relative masses of the three particles in the final state. We analyse the differences in the electron cusp formation by both heavy and light projectile impact at the double-differential cross section level.