Astrophysical background of antideuterons in cosmic rays

The nature of Dark Matter is one of the greatest mysteries in modern physics. One of the approaches developed over the years is the indirect search, which consists of looking for Standard Model particle signatures coming from Dark Matter particles’ decay or an- nihilation. Indirect searches are carried on with all the particle astrophysical messengers such as neutrinos, gamma rays, and charged cosmic rays. Among charged cosmic rays, a promising channel is the one that involves antinuclei, which are nuclei composed of antiprotons and antineutrons. These can be produced by exotic sources, such as Dark Matter, or by Standard Model processes involving collisions between charged cosmic rays and the nuclei composing the interstellar matter, representing the background signal. The object of this thesis consists of the evaluation of the flux of antideuterons, a bound state of an antiproton and an antineutron, from Standard Model processes. The work presented here is highly interdisciplinary since it involves hadron physics and cosmic ray propagation Physics. Hadron physics is essential because it is the starting point for the evaluation of the antideuteron production cross section, involving the use of Monte Carlo generators (PYTHIA) for the production of antinucleons, and the use of a sophisticated coalescence model to bind the antinucleons provided the formation probability of the antideuteron. On the other hand, the propagation of charged cosmic rays is also crucial since it provides the estimated flux starting from the extracted cross sections. Being able to estimate the background antideuteron flux is necessary to understand in what region it is more likely to find Dark Matter signals, and also to provide the requirements of future detectors that aim at the detection of the cosmic antideuteron signal.