Cosmic ray mass independent energy reconstruction method using Cherenkov light and muon content in LHAASO

Abstract

The wide field-of-view Cherenkov telescope array of the Large High Altitude Air Shower Observatory (LHAASO) measures the longitudinal development of Cherenkov light in the air shower of cosmic rays, while the kilometer-square array of LHAASO measures the number of muons in the air shower. The unique detector arrangement of LHAASO can facilitate the precise reconstruction of the cosmic ray energy in the knee region. Thus, this study proposed a new energy reconstruction method by simultaneously using the Cherenkov light size and the number of muons, which is insensitive to the primary particle type. Using this method, the energy bias and resolution of the light component (proton and helium) were less than 1% and 10% at approximately 1 PeV, respectively. Moreover, the difference in energy bias between helium and proton was less than 1% at approximately 1 PeV. In addition, the dependence of this energy reconstruction method on hadronic interaction models and cosmic ray components was also discussed.