NBIA Seminar: Rafael Alves Batista

A long-standing puzzle in astroparticle physics concerns the origins of the most energetic particles in the Universe. In the quest to identify their sources, it is essential to understand how they are accelerated, how they can escape the sites wherein they were produced, and which roads they can take on their journey to Earth. Ultra-high-energy cosmic rays (UHECRs) are the key to unveil the Universe at the highest energies. Their interactions with matter and radiation fields are responsible for the production of copious amounts of other messengers, such as photons and neutrinos. The multimessenger framework enabled by combining these messengers is a powerful tool for understanding high-energy processes taking place in extreme astrophysical environments. This talk will focus on the modelling of particle propagation in the Universe, including their interactions with photon fields and with the poorly understood cosmic magnetic fields. I will also discuss the potential role these messengers can play as probes of cosmology and of fundamental physics.