Arrival time distributions of air shower particles measured by LHAASO-KM2A

The arrival time distributions of air shower particles provide critical insights into the longitudinal development of extensive air showers and the properties of primary cosmic rays. This study analyses the temporal characteristics of secondary particles detected by the KM2A detectors of the Large High Altitude Air Shower Observatory (LHAASO). We propose a novel parameterized function to describe the temporal profiles of secondary electromagnetic and muon components, significantly improving the modeling accuracy of the shape and thickness of the shower disk. These findings provide a crucial tool for enhancing the accuracy of angular reconstruction algorithms, testing the predictions of high-energy hadronic interaction models, and improving the primary mass composition discrimination capabilities of the ground-based cosmic ray experiments.