A data analysis led by Team A01 using the IceCube experiment revealed that the number of ultra-high-energy neutrinos is significantly lower than expected. Leveraging this finding, the team demonstrated that the origin of ultra-high-energy cosmic rays is not protons, but rather heavy atomic nuclei. This result has been featured by numerous media outlets. For more details, please see here.
This research will be published in Physical Review Letters (PRL), a journal of the American Physical Society, on July 15, 2025. Furthermore, the paper has been selected as a PRL Editors’ Suggestion, highlighting it as a particularly important contribution, and will be featured on the PRL homepage.