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arXiv · 1903.03174

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

Luan Arbeletche·Vitor de Souza
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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 Sibyll2.3c. 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 were 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 the best functional form to describe the $X_{max}$ distribution. The Generalized Gumbel distribution is shown to be the best option 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.

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Luan Arbeletche, Vitor de Souza. 2019-03-07. On the parametrization of the distributions of depth of shower maximum of ultra-high energy extensive air showers. https://doi.org/10.1016/j.astropartphys.2019.102389

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