Properties of hadron families observed with thick-type emulsion chambers at Mts. Kanbala and Fuji and search for Centauro events

The properties of hadrons and gamma rays in the families observed with the thick-type emulsion chambers at Mt. Kanbala (5500 m above sea level) and Mt. Fuji (3750 m) are presented. The results from both experiments agree well with each other. The correlations were systematically examined between gamma rays and hadrons in the families, and their behavior appears to be almost consistent with a Monte Carlo simulation made on the assumption of the model of hadronic interactions which are scaled smoothly up to about ${10}^{16}$ eV in energy from the accelerator data. A search for Centauro candidates has been specially made in the family data obtained both at Mts. Kanbala and Fuji, with negative results. The upper limit of the fraction of such events is estimated to be 3% (95% confidence level) in the hadron families with energy greater than 100 TeV for each experiment. Other interesting results are also discussed on the structure of hadron families.