No abstract

The average number of muons in air showers and its connection with shower development has been studied extensively in the past. With the upcoming detector upgrades, UHECR observatories will be able to probe higher moments of the distribution of the number of muons. Here a study of the physics of the fluctuations of the muon content is presented. In addition to proving that the fluctuations must be dominated by the first interactions, we show that low-N µ tail of the shower-to-shower distribution of the number of muons is determined by the high-x L region of the production cross-section of neutral pions in the first interaction.

Ultra-high energy cosmic rays interact with nuclei of the Earth's atmosphere at ∼ 10 × √ 𝑠 of proton-proton collisions at the LHC and in extremely high rapidity regions, providing a unique opportunity to probe hadronic interactions in poorly explored regions of the kinematic phase space of p-air interactions. In this contribution, we show that fluctuations in the muon content of Extensive Air Showers correlate with fluctuations of the fraction of the primary energy that goes into hadronic channel of the primary p-air interaction. Furthermore, we show that measurements of the slope of the low tail of the muon number distribution in EAS constrain the forward inclusive cross-section for the production of neutral pions in-pair interactions at ∼ 450 TeV. Moreover, we explore the joint 𝑋 max − 𝑁 𝜇 distribution, demonstrating that the slope of the tail of the muon number distribution is sensitivity to 𝑋 max , in such a way that hadronic models converge for shallower 𝑋 max and diverge for deeper showers. In particular, we hint at the connection between these regimes and the presence of diffraction in p-air interactions.