Multielectronic Processes in Particle and Antiparticle Collisions with Rare Gases

In this chapter we analyze the multiple ionization by impact of |Z|=1 projectiles: electrons, positrons, protons and antiprotons. Differences and similarities among the cross sections by those four projectiles allows us to have an insight on the physics involved. Mass and charge effects, energy thresholds, and relative importance of collisional and post-collisional processes are discussed. For this purpose, we performed a detailed theoretical-experimental comparison for single up to quintuple ionization of Ne, Ar, Kr and Xe by particles and antiparticles. We include an extensive compilation of the available data for the sixteen collisional systems, and the theoretical cross sections by means of the continuum distorted wave eikonal initial state approximation. We underline here that post-collisional ionization is decisive to describe multiple ionization by light projectiles, covering almost the whole energy range, from threshold to high energies. The normalization of positron and antiproton measurements to electron impact ones, the lack of data in certain cases, and the future prospects are presented and discussed.

Keywords: Antiparticle, Antiproton, Electron, Ionization, Multiple ionization, Noble gases, Positron, Proton, Particle, Ne, Ar, Kr, Xe.