Speaker
Description
A study of antiproton-nucleus annihilations at rest has been conducted by directing slow-extracted antiprotons onto few um thick targets at the AEgIS facility at CERN. The experiment uses six Timepix4 ASICs coupled to 500 μm thick silicon sensors arranged in a cuboid geometry that covers the majority of the solid angle around the target. Using these detectors, the total multiplicity, energy and angular distributions of various prongs produced in the antiproton annihilation in the thin solid targets can be determined. These measurements allow to study the possible final state interactions triggered by the primary annihilation mesons, as well as their evolution with the nucleus mass and their branching ratios.
An algorithm for the 3D reconstruction of the annihilation vertex from particle tracks in the single-plane detectors has been developed using Geant4 and Fluka simulations together with the Allpix2 framework. Therefore, individual annihilation events can be tagged, allowing the discrimination between antiprotons annihilating on the target and those elsewhere. In this talk, preliminary results from both simulations and data, including the sub-mm achieved resolution on the vertex position will be presented and discussed.