Work

Measurements of the variance of the logarithmic mass of cosmic rays from 0.3 to 30 PeV with LHAASO-KM2A

Year: 2025

Type: conference-paper

Abstract: The Large High Altitude Air Shower Observatory (LHAASO) has accomplished comprehensive and precise measurements of very-high-energy cosmic ray air showers. For the first time, the logarithmic shower muon number has been employed to derive the mean logarithmic mass ($\langle \ln A \rangle$) of cosmic rays, while fluctuations in the logarithmic shower muon number have been utilized to construct the variance of the logarithmic mass ($\sigma_{\ln A}^{2}$). The analysis provides a clear depiction of the cosmic ray mass composition evolution with energy and explicitly illustrates the energy-dependent trend of $\sigma_{\ln A}^{2}$. The reliability of this parameterization method has been validated by employing simulations based on three different hadronic interaction models (QGSJET-II-04, EPOS-LHC, and SIBYLL 2.3d) with various cosmic ray compositions. The results demonstrate excellent consistency between the simulated input values of $\langle \ln A \rangle$ and $\sigma_{\ln A}^{2}$ and those derived from the parameterization, thus confirming the robustness and accuracy of this approach.

Source: International Cosmic Ray Conference

DOI: 10.22323/1.501.0251

Authors: Xiaoting Feng, Cunfeng Feng, Hengying Zhang, Lingling Ma

Institutions: Shandong University, Yunnan University

Language: English

Topic: Astrophysics and Cosmic Phenomena

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: National Natural Science Foundation of China, High Energy Physics

Award: G8675102104