Study on Hadronic Interaction Model Validation Based on the Yangbajing Hybrid Array Experiment

Abstract The precise measurement of the cosmic ray composition is a key objective of ground-based cosmic ray experiments. The primary challenge arises due to the significant uncertainties in high-energy hadronic interaction models. These models not only affect the theoretical description of the propagation and evolution of cosmic rays in the atmosphere, but also directly determine the physical interpretation of experimental observations. As one of the principal secondary particles produced in hadronic cascades, muons retain substantial information from the primary interactions owing to their strong penetrating power and small interaction cross-section with matter. This makes them an effective probe for validating hadronic interaction models. In this study, based on the air shower data acquired by Yangbajing hybrid array, a high-statistics measurement of the muon component in cosmic-ray-induced events was performed. Subsequent systematic comparisons between the experimental observations and predictions of major existing hadronic interaction models revealed overall consistency within the “knee” of the cosmic ray energy spectrum, thereby supporting the basic validity of existing models in this range. Additionally, the results of combined spectral and compositional analyses indicated a transition in cosmic ray mass composition around the “knee,” shifting from light-nuclei dominance to heavy-nuclei dominance. The findings of our study provide important insights into the applicability of hadronic interaction models in the TeV–PeV energy range and offer observational evidence for understanding not only the physical origin of the "knee" in the cosmic ray energy spectrum but also its compositional evolution mechanisms.