A new type of nuclear interactions in the ΣEγ≳1014 eV region

Centauro‐type and Mini‐Centauro‐type events are reported and discussed. They are events in which nuclear‐active particles (i.e. hadrons which do not undergo rapid photon decays) are produced without any sign of accompanying neutral pion emission. Estimated hadron multiplicity is ∠100 for Centauro‐type and ∠15 for Mini‐Centauro‐type.Up to the present moment, 5 examples of Centauro and 13 of Mini‐Centauro have been observed in the two‐storey emulsion chambers exposed on Mt. Chacaltaya, Bolivia (5220 m above sea level).The experimental results on energy and angular distributions are in agreement with the hypothesis that this type of events occur through production and decay of a fire‐ball with a rest energy of (200∠300) GeV/c2 for Centauro and ∠30 GeV/c2 for Mini‐Centauro events.