On the parametrization of the distributions of depth of shower maximum of ultra-high energy extensive air showers

Author(s)

Arbeletche, Luan B. ^[1] ; de Souza, Vitor ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, Av Trabalhadar Sao Carlense 400, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Astroparticle Physics; v. 116, MAR 2020.
• Web of Science Citations: 1

Abstract

The distribution of depth in which a cosmic ray air shower reaches its maximum number of particles (X-max) is studied and parametrized. Three functions are studied for proton, carbon, silicon, and iron primary particles with energies ranging from 10(17 )eV to 10(20) eV for three hadronic interaction models: EPOS-LHC, QGSJETII.04, and SJBYLL2.3c. The function which best describes the X-max distribution of a mixed composition is also studied. A very large number of simulated showers and a detailed analysis procedure are used to guarantee negligible effects of undersampling and of fitting in the final results. For the first time, a comparison of several functions is presented under the same assumption with the intention of selecting within them the best functional form to describe the X-max distribution. The Generalized Gumbel distribution is shown to be the best option among the options for a general description of all cases. The Log-normal distribution is also a good choice for some cases while the Exponentially Modified Gaussian distribution has shown to be the worst choice in almost all cases studied. All three functions are parametrized as a function of energy and primary mass. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 15/15897-1 - Cherenkov Telescope Array - CTA
• Grantee: Luiz Vitor de Souza Filho
• Support Opportunities: Research Projects - Thematic Grants