Antideuteron search in cosmic rays with the alpha magnetic spectrometer on the International Space Station

The Alpha Magnetic Spectrometer (AMS-02) is a magnetic spectrometer, operating on the International Space Station (ISS) since its launch, on may 2011, delivering Cosmic Rays (CR) spectra for many species at percent level precision. The AMS experiment, as a magnetic spectrometer, is capable of detect heavy isotopic antimatter, such as antideuterons, which are one of the most important channel in the indirect research of Dark Matter (DM): they are not produces in standard astrophysical sources, but only in collisions between CRs that are propagating through the Galaxy, ant the InterStellar Medium (ISM). The kinematic of these cosmic collision suppresses the antideuteron production in CRs with low kinetic energies (< 1 GeV/nuc), creating a depleted region that can be investigated for Dark Matter signals. The antideuteron production cross section allows to predict how many antideuterons are expected in Cosmic Rays: if too many were observed, there could be only produced by new physics. However, modeling the antideuteron production cross section is not straightforward. Few data on antideuteron production have been released by colliders and fixed target experiments, at the energies interesting for cosmic rays production In the first part of this thesis, I explore the AMS capabilities to identify antideuterons in 12.5 years of collected data (2011-2023), using both standard analysis techniques and Machine Learning (ML) techniques to reject the high amount of background that can fake an antideuteron signal in the detector. The second part is devoted to the modelization of the antideuteron production cross section, using colliders and fixed target experiment data. The model, is then implemented in the GALPROP v57 code that, together with the HelMod v4 code, predicts the amount of the antideuterons expected at the Earth. The prediction is compared with the AMS capabilities explored before.