Speaker
Description
The current generation of observatories has confirmed that ultra-high-energy cosmic rays (UHECRs) are not composed only of protons. In particular, analyses of the distributions of shower-maximum depths have revealed an increasing trend in the mass composition of particles with energies above approximately $2 \: \rm EeV$. Given that photodisintegration is the primary interaction for nuclei heavier than protons propagating through intergalactic space, accurately modeling this process is essential for discovering their astrophysical origins.
To address this need, we present updates to the Monte Carlo propagation code SimProp, with an emphasis on its transition to the Sirente version. Central to these updates is the refinement of photodisintegration cross sections. Using the latest version of TALYS, a software for nuclear reaction models, we have recalculated the cross sections for the most critical interaction channels. As a practical application of our enhanced model, we compare the UHECR nuclei horizons derived from the previous and updated versions of SimProp and highlight the implications of these advancements for interpreting the UHECR energy spectrum and composition measurements.
To conclude, we also motivate the addition of a new photodisintegration model for ultra-heavy ($A > 56$) UHECRs, which have recently gained attention due to their potential role in the composition of the most energetic cosmic rays detected.
