FLUKA cross sections for cosmic-ray interactions with the DRAGON2 code

TL;DR

This paper develops and tests new cosmic-ray interaction cross sections using FLUKA, integrating them into models to improve predictions of secondary particle fluxes and gamma-ray emissions consistent with observational data.

Contribution

The paper introduces a new set of FLUKA-based cross sections for cosmic-ray interactions, enhancing model accuracy for secondary particles and gamma-ray predictions.

Findings

Good agreement with experimental data for cross sections.

Accurate reproduction of B, Be, Li flux ratios with less than 20% scaling.

Diffuse gamma-ray maps match Fermi-LAT observations.

Abstract

Secondary particles produced in spallation reactions of cosmic rays with the interstellar gas provide valuable information that allow us to investigate the injection and transport of charged particles in the Galaxy. A good understanding of the cross sections of production of these particles is crucial to correctly interpret our models, although the existing experimental data is very scarce and uncertain. We have developed a new set of cross sections, both inelastic and inclusive, computed with the {\tt FLUKA} Monte Carlo nuclear code and tested its compatibility with CR data. Inelastic and inclusive cross sections have been compared to the most up-to-date data and parameterisations finding a general good agreement. Then, these cross sections have been implemented in the {\tt DRAGON2} code to characterize the spectra of CR nuclei up to $Z=26$ and the secondary-to-primary ratios of B, Be and Li. Interestingly, we find that the FLUKA cross sections allow us to predict an energy-dependence of the B, Be and Li flux ratios which is compatible with AMS-02 data and to reproduce simultaneously these flux ratios with a scaling lower than $20\%$. Finally, we implement the cross sections of production of gamma rays, calculated with {\tt FLUKA}, in the {\tt Gammasky} code and compute diffuse gamma-ray sky maps and the local HI emissivity spectrum, finding a very good agreement with Fermi Large Area Telescope data.