Estimation of the invisible energy with the data collected by the Pierre Auger Observatory

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

Simposio; UHECR 2016; 2016

The determination of the energy of primary cosmic rays from their extensive air showersusing the fluorescence technique requires an estimation of the energy carried away by particlesreaching the ground that do not deposit all their energy in the atmosphere. This estimation istypically made using Monte Carlo simulations and depends on the assumed primary particlemass and on model predictions for hadron-air collisions at high energies. In this work wereview the method that the Pierre Auger Collaboration uses to obtain the invisible energydirectly from hybrid events measured simultaneously with the fluorescence and the surfacedetectors of the Pierre Auger Observatory. As a corroboration of these results, a new methodfor the determination of the invisible energy using an independent data set is also presented.Both methods agree within systematic uncertainties, reducing significantly the biases relatedto differences between the high energy hadronic interaction models and data.