Researchers find a possible solution to the cosmic ray muon puzzle

Scientists have a problem with cosmic rays—they produce too many muons at the Earth's surface. Cascades of muons are byproducts of high-energy cosmic rays as they collide with nuclei in the upper atmosphere, and scientists see more muons at Earth's surface than standard physics models predict.

source https://phys.org/news/2024-11-solution-cosmic-ray-muon-puzzle.html