Cosmic Rays are charged particles, mostly protons (85-90%), helium (5-10%), heavier nuclei (1%), and electrons (<1%), coming from space and produced in the most energetic events in our Galaxy and beyond, in particular in Supernovae explosions. The exact origin of Cosmic Rays remains a mystery up to now, more than a century since their discovery by Victor Hess in 1912. The absolute majority of cosmic rays have the energy of about a few hundred Megaelectronvolts and are deflected away by the earth's magnetic field. Yet a smaller portion of them can reach energies almost a billion times higher than those of the particles accelerated at the Large Hadron Collider. Comic Rays are the ultimate laboratory of the Universe study, in particular of the events driving the evolution of Galaxies the structure of the interstellar medium, chemical composition and generation of elements in stars. It is generally believed that Galactic sources are capable of accelerating Cosmic Rays up to a few Petaelectronvolt (PeV), while everything with higher energy comes outside the Galaxy. For a long time, a conventional hypothesis dominated that Galactic Cosmic Rays (GCR) are produced in the Supernovae Remnants (SNR) and their spectrum represents a simple power-law with a fixed spectral index. Recent direct measurements performed in the past decade by space missions challenge the conventional models, revealing peculiar structures in the spectrum of various cosmic ray components at the energy of about Teraelectronvolt (TeV). This is suggestive of a new source type of cosmic rays or an unknown acceleration or propagation effect. Further high-precision measurements of spectra of different cosmic ray components beyond the TeV scale are essential for solving the puzzle of GCR origin and will also help to pinpoint the possible Dark Matter signatures, which may manifest themselves in the spectrum of Cosmic Rays, notably electrons. Such measurements, however, are hampered by the systematic uncertainties due to the limited accuracy of Cosmic Ray particle reconstruction and identification techniques, and the relatively low precision of hadronic Monte-Carlo simulation models.
The main objective of this project is to radically improve and optimize the techniques for Cosmic Ray detection at TeV—PeV energy region, including particle reconstruction, identification, and simulation, using a state-of-the-art Artificial Intelligence (AI) approach. As a result, Cosmic Ray spectra and composition will be measured first with the DArk Matte Particle Explorer (DAMPE) space mission and then subsequently with the next-generation space instrument — High Energy Radiation Detector (HERD), with unprecedented precision, which could not be achieved otherwise. There are two main innovations in the project. First, the application of AI techniques in astroparticle physics will be pioneered at the highest energies, in an unconventional use case. Second, the Monte-Carlo hadronic simulation models will be tested and tuned using the detector data, for the first time at such high energies.
In conclusion of the project, the developed AI methods have radically outperformed the classical algorithms, enabling high-precision measurements beyond the previous state-of-the art maximum energy of ~100 TeV. Next, the pioneering measurements of strong interactions in space were performed at the highest energy frontier. Consequently, landmark results in cosmic ray physics were attained, among which is the first direct observation of a universal structure (the so-called spectral softening) in all major primary cosmic rays. It validates a long-established hypothesis: maximum energy of cosmic ray acceleration in astrophysical sources is charge dependent.
