A new approach to the study of high energy muon bundles with the MACRO detector at Gran Sasso

Abstract

The MACRO experiment detected more than 300000 multiple muon events. We analysed these events to measure the distribution of the separation of underground TeV muons (decoherence function), up to a distance of 70 meters. On a subsample of very high multiplicity events, we performed two independent analyses, based on the study of the spatial structure of the bundles. Both the analyses revealed a correlation between the topology of the bundles and the dynamics of the shower development in atmosphere. These results have been used to constrain and disentangle the primary composition and the hadronic interaction models used by different shower propagation codes (HEMAS-DPM/CORSIKA).