Multielectronic processes in particle and antiparticle collisions with rare gases

TL;DR

This paper compares multiple ionization processes caused by electrons, positrons, protons, and antiprotons impacting rare gases, highlighting the physics of charge and mass effects through theoretical and experimental analysis.

Contribution

It provides a comprehensive comparison of experimental and theoretical cross sections for multiple ionization by particles and antiparticles in rare gases, emphasizing post-collisional effects.

Findings

Post-collisional ionization is crucial for light projectiles across all energies.

Theoretical models align well with experimental data for most collisional systems.

Positron and antiproton data are normalized to electron impact results.

Abstract

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 these 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.