AI and the World's Hard Problems · Astronomy & space · arXiv · 2026-10-23
Search for Ultra-Relativistic Magnetic Monopoles with LHAASO-KM2A
Ultra-relativistic magnetic monopoles crossing the atmosphere are expected to produce air showers with a muon deficit and a compact lateral profile. The authors searched 1438.81 live days of LHAASO-KM2A data with a machine-learning classifier that separates monopole signals from hadronic background using lateral shower shape. Finding no excess, they set 90% confidence upper limits on the isotropic monopole flux, improving on the astrophysical Parker bound by over three orders of magnitude and constraining a previously unconstrained velocity window.