Abstact: The origin of ultra-high-energy cosmic rays (UHECR) with energies $E \ge 10^{20}$ eV remains mysterious, since they cannot be explained by standard stellar processes. In this talk, a new approach is proposed suggesting that these extremely high-energy cosmic rays could originate from superheavy dark matter particles. We consider the cosmological evolution in $R^2$-modified gravity (the Starobinsky model), where the post-inflationary dynamics and universe heating differ significantly from General Relativity. The suggested process of cosmological evolution allows for the existence of superheavy dark matter particles with masses up to $\sim 10^{13}$ GeV.
Specifically, we discuss two mechanisms for UHECR production from these relics: their resonance-enhanced annihilation in dense regions such as the Galactic Center, and their decay via virtual black holes in multidimensional gravity. Both processes provide a viable explanation for the UHECR fluxes currently observed by the Pierre Auger Observatory and Telescope Array.
Short bio: Dr. Elena V. Arbuzova is a Professor at the Department of Higher Mathematics at Dubna State University and a Senior Scientific Researcher at the Laboratory of Cosmology and Elementary Particle Physics at Novosibirsk State University, Russia. She received her PhD and Doctor Habilitatus (Dr. of Science) degrees in Physics from M.V. Lomonosov Moscow State University. Her primary research interests focus on general relativity, cosmology, modified gravity, baryogenesis, dark matter, and high energy cosmic rays. Dr. Arbuzova is an active researcher and frequently presents her work as an invited speaker at various international conferences on astrophysics and high-energy physics.