Muon deficit in simulations of air showers inferred from AGASA data

F. GESUALDI; A.D. SUPANITSKY; A. ETCHEGOYEN

Conferencia; 37th International Cosmic Ray Conference; 2021

Multiple experiments reported evidences of a muon deficit in air shower simulations with respectto data, which increases with the primary energy. In this work, we study the muon deficitusing measurements of the muon density at 1000 m from the shower axis obtained by the AkenoGiant Air Shower Array (AGASA). The selected events have reconstructed energies in the range18.83 ≤ log 10 (E_R /eV) ≤ 19.46 and zenith angles θ ≤ 36º . We compare these muon densitymeasurements to proton, iron, and mixed composition scenarios, obtained by using the high-energy hadronic interaction models EPOS-LHC, QGSJetII-04, and Sibyll2.3c. We find thatAGASA data are compatible with a heavier composition, lying above the predictions of the mixedcomposition scenarios. The average muon density divided by the energy in AGASA data isgreater than in the mixed composition scenarios by a factor of 1.49 +- 0.11 (stat) +0.49-0.30 (syst),1.54 +- 0.12 (stat) +0.50-0.31 (syst), and 1.66 +- 0.13 (stat) +0.54- 0.34 (syst) for EPOS-LHC, Sibyll2.3c, and QGSJetII-04, respectively. We interpret this as further evidence of a muon deficit in air shower simulations at the highest energies.