In the PMNS matrix, the relation $|U_{\mu i}| = |U_{\tau i}|$ (with $i = 1, 2, 3$) is currently favored by experimental data. This observation has sparked significant interest in the neutrino community due to its potential link to an underlying flavor symmetry. In this paper, we explore the implications of the condition $|U_{\mu i}| = |U_{\tau i}|$ within the framework of the canonical seesaw...
The interpretation of extensive air shower (EAS) measurements strongly depends on detailed air shower simulations. CORSIKA is one of the most commonly used air shower Monte Carlo program. The main source of uncertainty in the prediction of shower observables for different primary particles and energies being currently dominated by differences between hadronic interaction models even after the...
The origin and nature of cosmic rays in the EeV energy range remain one of the major open questions in astroparticle physics. Their energies far exceed those attainable by human-made accelerators, and their extremely low flux makes direct detection by space-based instruments unfeasible. For over two decades, the Pierre Auger Observatory—a 3000 km² array of instruments spread across the...
The measurement of hadronic interaction cross-sections at the highest cosmic-ray energies provides a unique opportunity to probe soft QCD processes beyond the reach of existing accelerator experiments. A key observable for such studies is the atmospheric depth at which air showers reach their maximum development ($X_\mathrm{max}$), which is sensitive to both the mass of the primary cosmic rays...
The search for origin of the most energetic cosmic rays has been mainly obscured by uncertainties in their mass composition arising from the modelling of hadronic interactions in the air showers that these particles induce. For some time now, discrepancies between the model predictions and measured air-shower data have been complicating efforts to find a consistent mass-composition scenario of...
Extensive air showers (EAS) triggered by ultra-high-energy cosmic rays (UHECRs) are driven by hadronic interactions with low momentum transfer, which cannot be described by perturbative QCD. Moreover, the phenomenological models employed in simulating such interactions lack constraints from accelerator measurements in the relevant phase-space region for shower development. This leads to large...
