Overview
- An Oxford-led team used CERN’s Super Proton Synchrotron at the HiRadMat facility to generate electron–positron pairs and drive them through a meter-long ambient plasma as a scaled analogue of blazar cascades.
- Measurements showed the pair beam stayed narrow with minimal self-generated magnetic fields, indicating suppressed beam–plasma instabilities in the laboratory setup.
- The findings imply such instabilities are too weak to account for the missing secondary GeV emission from blazars, shifting weight toward deflection by weak intergalactic magnetic fields.
- The study was published in the Proceedings of the National Academy of Sciences on November 3, 2025 (DOI: 10.1073/pnas.2513365122).
- Researchers highlight unresolved questions about the origin of intergalactic magnetism and point to upcoming tests with facilities such as the Cherenkov Telescope Array Observatory.