Simulation study on the effects of diffractive collisions on the prediction of the observables in ultra-high-energy cosmic ray experiments

TL;DR

This study investigates how detailed characteristics of diffractive collisions influence the predictions of observables in ultra-high-energy cosmic ray experiments, highlighting the impact of cross-sectional fractions on key measurements.

Contribution

It provides a detailed analysis of the effects of diffractive collision characteristics on cosmic ray observables, emphasizing the significance of cross-sectional fractions in uncertainty estimation.

Findings

Uncertainty in cross-sectional fractions affects $ ext{X}_{ ext{max}}$ by 8.9 g/cm^2.

Diffractive-mass spectrum has minor effects on observables.

Current models' uncertainties significantly impact cosmic ray composition interpretation.

Abstract

The mass composition of ultra-high-energy cosmic rays is important for understanding their origin. Owing to our limited knowledge of the hadronic interaction, the interpretations of the mass composition from observations include several open problems, such as the inconsistent interpretations of $\langle X_{\mathrm{max}}\rangle $ and $\langle X_{\mathrm{max}}^{\mu}\rangle $. Futhermore, the large difference between the predictions exists by the hadronic interaction models. Diffractive collision is one of the proposed sources of the uncertainty. In this paper, we discuss the effect of the detailed characteristics of diffractive collisions to the observables of ultra-high-energy cosmic-ray experiments, focusing on three detailed characteristics. These are the cross-sectional fractions of different collision types, diffractive-mass spectrum, and diffractive-mass-dependent particle productions from the diffractive dissociation system. We demonstrated that the current level of the uncertainty in the cross-sectional fraction can affect 8.9 $\mathrm{g/cm^2}$ of $\langle X_{\mathrm{max}}\rangle $ and 9.4 $\mathrm{g/cm^2}$ of $\langle X_{\mathrm{max}}^{\mu}\rangle $, whereas the other details of the diffractive collisions exhibit relatively minor effects.