Cosmic rays are charged particles that enter the Earth’s atmosphere where they in-
teract with air molecules at energies of more than 10 times the center-of-mass energy
at the Large Hadron Collider at CERN. These interactions produce particle cascades in
the atmosphere, so-called extensive air showers, which can be measured at the ground
with large detector arrays. The properties of the initial cosmic ray, such as its energy
and mass, are inferred indirectly from the particles measured at the ground and their
interpretation strongly relies on simulations of the shower development. In recent years,
however, various measurements have shown large discrepancies with respect to current
model predictions, indicating shortcomings in our understanding of particle physics which
can only be explained in the context of unconventional or new physics.
IceCube is located at the geographic South Pole and it consists of a cubic-kilometer
Cherenkov detector deep in the Antarctic ice, accompanied by a square-kilometer surface
detector. With this hybrid detector setup, IceCube yields various opportunities to study
cosmic rays in great detail and thereby reduce the remaining model uncertainties.
In this talk, I will review the current state of the field and present recent results of
cosmic ray measurements with IceCube. In particular, I will highlight IceCube’s unique
opportunities to provide important information about particle interactions in extensive
air showers. I will discuss the synergies between cosmic ray and particle physics in the
multi-messenger era and conclude by showing how measurements with IceCube open a
new window for interdisciplinary