Speaker
Description
Cosmic rays are the most energetic particles observed in the Universe.
Although extremely rare, a handful of events with energies exceeding
$10^{20}\,\mathrm{eV}$ have been detected. This corresponds to about
$16\,\mathrm{J}1$ concentrated in a single particle and to an equivalent
thermal energy scale of approximately $10^{24}\,\mathrm{K}$, comparable
to that of the Universe roughly $10^{-29}\,\mathrm{s}$ after the Big
Bang. We now know that cosmic rays have a surprisingly continuous,
almost featureless non-thermal energy spectrum spanning over ten orders
of magnitude. Their study has led to the discovery of several particles
and to the birth of particle physics. Even today, particle physics and
cosmic-ray physics remain closely connected and continue to benefit from
one another. Despite major advances, fundamental questions remain
unanswered, particularly regarding the astrophysical origin of cosmic
rays and the mechanisms that can accelerate these particles to such
extreme energies. Multimessenger astrophysics is the most promising path
towards answering these questions. In this talk, I will briefly guide
you through our understanding of cosmic rays over time. Along this
timeline, I will present a set of selected contributions from our group
to address several still-open questions.