Estimation of the invisible energy in extensive air showers with the data collected by the Pierre Auger Observatory

A. MARIAZZI; THE PIERRE AUGER COLLABORATION.; M. TUEROS; S. J. SCIUTTO

Kyoto

Conferencia; 2016 International Conference on Ultra-High Energy Cosmic Rays (UHECR2016); 2016

University of Tokyo

The determination of the energy of primary cosmic rays from their extensive air showers using thefluorescence technique requires an estimation of the energy carried away by particles reaching theground that do not deposit all their energy in the atmosphere. This estimation is typically madeusing Monte Carlo simulations and depends on the assumed primary particle mass and on modelpredictions for hadron-air collisions at high energies. In this work we review the method that thePierre Auger Collaboration uses to obtain the invisible energy directly from hybrid events measuredsimultaneously with the fluorescence and the surface detectors of the Pierre Auger Observatory. Asa corroboration of these results, a new method for the determination of the invisible energy using anindependent data set is also presented. Both methods agree within systematic uncertainties, reducingsignificantly the biases related to differences between the high energy hadronic interaction modelsand data.