Analysis of experimental data for ion-impact single ionization of helium with Monte Carlo event generators based on quantum theory

Recent multiply differential experimental data taken with reaction microscopes severely challenge predictions of quantum mechanical few-body models. Here, we report on a thorough analysis of all known possible experimental resolution effects and their influence on the extracted cross sections. Using a Monte Carlo event generator to simulate true events on the basis of quantum calculations allows us to consistently incorporate all aspects of the experimental resolution of the reaction microscope. We study the effect of the instrumental function in single ionization of helium by 3.6 MeV/u Au53+ and 100 MeV/u C6+ ions and find it to significantly modify the simulated theoretical predictions. Nevertheless strong discrepancies between simulated and experimental data persist. Structures in the measured cross sections reported earlier, which could not be reproduced by theory, are thus not solely due to the experimental resolution. Our study suggests that the method using event generators, as routinely done in high-energy physics, provides the ultimate pathway of benchmarking calculations against experimental data on few-particle reactions studied with modern imaging techniques