A systematic study of the hybrid experiment at Mt.Chacaltaya

¹ Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Japan
² Faculty of Science, Soka University, Hachioji, Tokyo, Japan
³ Faculty of Engineering, University of Yamanashi, Kofu, Japan
⁴ Faculty of Science, Saitama University, Saitama, Japan
⁵ aculty of Education, University of Yamanashi, Kofu, Japan
⁶ Insitute de Investigaciones Fisicas, Universidad Mayor de San Andres, La Paz, Bolivia
⁷ General Education, Yonago National College of Technology, Yonago, Japan
⁸ Faculty of Science, Kochi University, Kochi, Japan
⁹ Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Japan
¹⁰ Faculty of Comprehensive Welfare, Urawa University, Urawa, Japan

^a e-mail: tamada@ele.kindai.ac.jp

Abstract

In the hybrid experiment on Mt.Chacaltaya, we can observe three different components of airshowers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles). Burst-density in each block of hadron calorimeters are newly recalculated in simulations in oder to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in the air-showers simulated using CORSIKA, and are converted into burst-density, taking into consideration the exact structure of experimental hadron calorimeter. We study correlations among three observable components in the air-showers. Correlations between air-shower size and burst-density and those between air-shower size and accompanied family energy can be explained by model calculations by adjusting primary particle composition, the former correlation is in favor of proton-primaries but the latter iron-primaries. No model can describe well observed correlations between burst-density and family energy. That is, the observed family energy accompanied by the air-showers with larger burst-density is systematically smaller than that expected in the simulated events. Effects of a fluctuation in the cross-section of hadronic interactions are studied to settle the disagreement between experimental data and simulations.