The study measures particle production and the cross section of proton–oxygen collisions, yielding data far more precise than the differences among existing shower models.

Angantyr captures particle energies and directions well, but it does not describe all results consistently, revealing detector blind spots that favor large-angle tracks and miss energy near the beam pipe.

Findings will help determine the hydrogen-to-heavy-element composition of high-energy cosmic rays, offering clues about their origins in extreme cosmic environments like exploding stars and supermassive black holes.

The study analyzed about 246 million collisions with around 5.11 billion reconstructed tracks, showing that current cosmic-ray interaction models do not reproduce all observed features.

This work links accelerator physics and high-energy astrophysics by providing controlled measurements that constrain atmospheric cascade development, refining interpretations at ground-based cosmic-ray observatories.

The goal was to resolve discrepancies among computer models predicting particle showers by providing empirical data from real CERN collisions.

The dataset will be used to retune air-shower simulations, improving estimates of cosmic-ray energy, composition, and origins, especially at energies unreachable by direct measurements.

CERN researchers used the ATLAS experiment to recreate proton–oxygen collisions at 9.62 TeV per nucleon pair to mimic atmospheric cosmic-ray interactions.

A proton beam represented cosmic rays and an oxygen beam represented Earth’s atmosphere, producing a spray of particles that mirrors atmospheric cascades.

This study marks the first laboratory recreation of cosmic ray showers by colliding oxygen with protons at the Large Hadron Collider to simulate cosmic rain in the lab.

The measured cross section is at the low end of model predictions and agrees with only two of seven tested models; the inferred proton–air cross section aligns with prior air-shower measurements.

Measured fiducial proton–oxygen cross sections (about 396 mb) and inferred proton–air cross sections (about 406 mb) support the lower end of model predictions and align with previous cosmic-ray results.