A new basic air shower observable sensitive to the cosmic-ray elemental mass

Abstract

Based on a Monte Carlo simulation study of vertical extensive air showers (EAS) at the KASCADE location we introduce a new simple observable ${\eta }_{\rho (45;310)}$ (in short ${\eta }_{\rho }$) - the ratio between two lateral electron densities of an EAS measured at two well-defined radial distances indicated by the characteristic radial feature of the local age parameter (LAP). Our analyses of simulated data generated by the Group I nuclei with cosmic-ray elemental masses, $A_{\text{actual}}=1,4,12,16,24,32,40,56$, observed a double correlation of ${\eta }_{\rho }$ with, (i) the lateral shower age $s_{\text{av}}$, and (ii) $A_{\text{actual}}$ of the EAS initiating primary particle. Applying the first correlation to a new set of simulated showers initiated by the Group II nuclei with $A_{\text{actual}}=7,14,20,28,40,52$, the average difference between the lateral shower age $s_{\text{av}}$ obtained directly from the conventional LAP approach and the estimated one $s_{\text{est}}$ is found to be close to $0$. The second correlation involving ${\eta }_{\rho }$ with $A_{\text{actual}}$ applied to the set of such showers estimates the average atomic mass $<\ln A_{\text{est}}>$ of their shower initiating primaries, utilizing the ${\eta }_{\rho }$s. Results of the work revealed that the method of estimating the lateral shower age is almost high-energy interaction model-independent. A certain level of model dependence is albeit found in the case of $<\ln A_{\text{est}}>$ estimation.

18 pages, 43 figures

References in corpus (20)

• Relativistic Hadron-Hadron Collisions in the Ultra-Relativistic Quantum Molecular Dynamics Model (UrQMD)
• EPOS LHC : test of collective hadronization with LHC data
• The Pierre Auger Cosmic Ray Observatory
• The surface detector array of the Telescope Array experiment
• Energy determination in the Akeno Giant Air Shower Array experiment
• Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory
• Ultrahigh Energy Cosmic Rays
• Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode
• Reconstruction of the energy and depth of maximum of cosmic-ray air-showers from LOPES radio measurements
• The depth of maximum shower development and its fluctuations: cosmic ray mass composition at E_0 >= 10^17 eV
• Applying Shower Development Universality to KASCADE Data
• Design, upgrade and characterization of the silicon photomultiplier front-end for the AMIGA detector at the Pierre Auger Observatory
• The angular resolution of GRAPES-3 EAS array after correction for the shower front curvature
• LOPES-3D, an antenna array for full signal detection of air-shower radio emission
• The spectra and composition of Ultra High Energy Cosmic Rays and the measurement of the proton-air cross section
• Slope of the lateral density function of extensive air showers around the knee region as an indicator of shower age
• A novel approach for deducing the mass composition of cosmic rays from lateral densities of EAS particles
• Composition determination of cosmic rays from the muon content of the showers
• Explaining the characteristics of lateral shower age of cosmic ray extensive air showers
• The shape of the electron and muon lateral distribution functions of extensive air showers