S8 - Felix Riehn, Ultra High Energy Cosmic Rays
30 Novembro 2022, 14:00 • Maria Margarida Cruz
Abstract: Cosmic Rays (CRs) are high-energy particles, impinging
on the Earth from outer space. Most of them are ionized atomic nuclei.
CRs with energies exceeding 10^20 eV have been measured. This is
outstandingly high, nearly a million times higher than the record of
human-made accelerators, the LHC. Very few astrophysical objects seem
capable of reaching such energy levels and it is still a mystery how
they can achieve it. The Pierre Auger Observatory, located near the town
Malargüe in Argentina, is the world's largest detector for CRs. The
scientific questions it tries to answer are: What are the sources and
acceleration mechanisms of ultra high energy CRs? Do we understand
particle acceleration and physics at energies well beyond the LHC scale?
What is the fraction of protons, photons, and neutrinos in cosmic rays
at the highest energies? Moreover, understanding these processes will
shed light into the unknown mechanisms driving the most extreme objects
of the Universe. In this seminar I will explain how CRs are detected at
the Pierre Auger Observatory, give a brief overview of our current
understanding of the origin of CRs, and hint at what we hope to learn in
the future.