Antiproton annihilation at rest in thin solid targets and comparison with Monte Carlo simulations

TL;DR

This study measures charged particle multiplicities from antiproton annihilations at rest on various nuclei and compares results with simulation models, highlighting the need for improved models and further low-energy measurements.

Contribution

It provides experimental data on antiproton annihilation at rest on different nuclei and evaluates the accuracy of existing simulation models against these measurements.

Findings

Charged particle multiplicities vary with target nucleus.

Current models do not fully reproduce experimental results.

Further low-energy measurements are needed to improve models.

Abstract

The mechanism of antiproton-nucleus annihilation at rest is not fully understood, despite substantial previous experimental and theoretical work. In this study we used slow extracted antiprotons from the ASACUSA apparatus at CERN to measure the charged particle multiplicities and their energy deposits from antiproton annihilations at rest on three different nuclei: carbon, molybdenum and gold. The results are compared with predictions from different models in the simulation tools Geant4 and FLUKA. A model that accounts for all the observed features is still missing, as well as measurements at low energies, to validate such models.