Search for elusive neutrino multiplets tightens limits on cosmic particle origins

The origins of extremely high-energy particles that fill the universe—such as protons, electrons, and neutrinos—remain one of the longest-standing mysteries in modern astrophysics. A leading hypothesis suggests that “explosive transients,” including massive stellar explosions (supernovae) and tidal disruption events (TDE) caused by stars being torn apart by black holes, could be the cosmic engines driving these energetic particles. Yet, this idea has never been rigorously tested.