Air-shower-triggered families: simulation calculation and its comparison with experimental data

Results of Monte Carlo simulations for a combined emulsion chamber and extensive air-shower array experiment are shown. Two totally distinct models are assumed for nuclear interactions, one based on the UA5 Monte Carlo algorithm (model A) and the other including exotic processes of Centauro and MiniCentauro (model B). Effects of different assumptions on the chemical composition of primary particles are also considered. Longitudinal and also lateral structures of gamma-families triggered by air-shower size, Ne, are studied and are compared with the data of the HADRON experiment at Tien-Shan and of the SYS experiment at Chacaltaya. The experimental data are found to disagree with the results of model A, even when we introduce the heavy-dominant assumption for primary cosmic rays. On the other hand, model B explains the general tendency of the experimental characteristics. It suggests that the nuclear interaction is changed drastically in the primary energy range over 1016 eV.