Frontpage>What
is Astroparticle Physics?
Astroparticle
physics is a new field of research
emerging from the convergence of physics at the smallest and the largest
scales of the Universe. In particle physics we investigate the intimate
structure of matter and the laws that govern it. In astronomy and
astrophysics, we study the structure of the Universe and its evolution
from the initial hot Big Bang. It is cosmology that links the theory
of particle physics with that of the very early Universe. Any discovery
in particle physics has an immediate consequence on the understanding
of the Universe and, inversely, discoveries in cosmology have fundamental
impact on theories of the infinitely small.
Until the early 1950s, cosmic rays - charged high-energy particles
from outer space –were our main source of information for advances
in knowledge about the nature of matter in the Universe. Then, particle
accelerators opened the path to tremendous progress, providing high-energy
particle beams to investigate the structure of matter. Today, however,
we are going back to study cosmic rays because new kinds of detectors
allow us to detect cosmic rays with energies far beyond the limits
of accelerators.
As the field of Astroparticle Physics develops, it is opening up new
observing windows in astronomy. For the first time, light or more
generally electromagnetic waves are not the only messengers from distant
objects in the Universe, as we begin to observe very high-energy cosmic
rays, neutrinos, or gravitational waves.
By comparing observations through different windows and at various
energies, we aim to learn more about high-energy cosmic phenomena
in the Universe and the violent processes that give rise to them.
A series of astrophysical objects demand an interdisciplinary, multi-wavelength
and multi-messenger approach for their comprehension. Furthermore,
astrophysical sites of violent phenomena can be used as a laboratory
to test the structure of the fundamental laws of particle physics
and gravitation.
On the instrumentation and methodology side, particle physics detector
techniques are used to detect astrophysical objects and conversely
astrophysics methods are used to study topics of importance to particle
physics (e.g. dark matter and energy).
Up to now, many pioneering experiments in Astroparticle Physics have
been on a scale whereby they could be implemented by small teams funded
nationally. This has now changed such that, except for some specific
topics the most promising new projects need large multidisciplinary
teams on a European scale or even world level. The rapid development
of the field has led to the design and the construction of infrastructures
whose size, complexity and cost reach often levels requiring the cooperation
of several scientific teams from different countries. These infrastructures
are of three kinds: