Exploring the electromagnetic shower profile to enhance the Pierre Auger Observatory physics capabilities

This work investigates two complementary strategies to enhance the physics capabilities of the Pierre Auger Observatory. The first examines the identification of vertical neutrino-induced air showers using the electromagnetic and muonic surface signals, Sem and Sμ. Simulations of proton and neutrino primaries using CORSIKA and the Auger Offline framework indicate that Xmax should not be directly included, as its information is largely encoded in Sem and Sμ. Additionally, it was shown that muon neutrino-induced showers can also be detected using the above Sem - Sμ methodology, offering a meaningful improvement in differential neutrino flux limits.

In the second part of this thesis, it is investigated the technique of radio interferometry as a method for reconstructing the electromagnetic longitudinal profile of extensive air showers. Using ZHAireS simulations, it was shown that there is a strong link between the EM profile shape and the one reconstructed from radio simulations. Significant differences in the longitudinal shape parameters, R e L, were observed between averaged showers of different primary compositions, demonstrating the technique’s potential for primary composition studies at full duty-cycle.

These results highlight the complementary impact of surface signal analysis and radio interferometry, while muon neutrinos can enhance neutrino detection limits, RIT provides an independent, high-precision method to access shower development, offering a promising avenue for improving ultra-high-energy cosmic-ray and neutrino observations.