Depth of Maximum of EAS and Mean Mass Composition of Primary CRs from the Spatial and Temporal Distribution of Cherenkov Light According to TAIGA-HiSCORE Data

Abstract

We present the dependence of the depth of maximum of extensive air showers (EAS), $X_{\max }$, on the energy of the primary particle, as determined from data recorded with the wide-angle Cherenkov array TAIGA-HiSCORE during the 2021--2025 observation seasons. The reconstruction of $X_{\max }$ from the experimental data uses relations obtained from EAS simulations: the dependence on the steepness of the Cherenkov light lateral distribution function ($P$-method) and on the full width at half maximum of the Cherenkov light pulse ($\tau$-method). The reconstructed $X_{\max }$ values are converted into the mean logarithmic mass $⟨\ln A⟩$, which characterizes the primary cosmic-ray mass composition. The results are compared with measurements from Tunka-133 (2017), the Pierre Auger Observatory (2019), LHAASO (2024), TALE (2026), and other experiments.

arXiv comment9 pages, 4 figures, 2 tables