Measuring the attenuation length of muon number in the air shower with muon detectors of 3/4 LHAASO array

TL;DR

This study measures how muon numbers in high-energy air showers decrease with atmospheric depth using LHAASO detectors, providing insights into shower development and energy dependence.

Contribution

It introduces a method to determine the muon attenuation length across a wide energy range using LHAASO data and compares results with simulations.

Findings

Muon attenuation length varies with shower energy.

Measured attenuation lengths are consistent with simulation predictions.

Provides data for understanding high-energy cosmic ray interactions.

Abstract

LHAASO KM2A consists of 5915 scintillation detectors and 1188 muon detectors, and the muon detectors cover 4% area of the whole array with 30 m spacing. The muon number of air shower events, with very high energy, is investigated with the data recorded by muon detector of the 3/4 LHAASO array in 2021. The attenuation length of muon number in the air shower is measured by fitting the muon number with constant flux in various zenith angles, based on the constant intensity cut method. The variation of the attenuation length as shower energy from hundreds TeV to tens PeV is presented. The results of simulation also is presented for comparing.