Fyzikální ústav Akademie věd ČR

Muons in air showers at the Pierre Auger Observatory: Measurement of atmospheric production depth

The Pierre Auger Collaboration (A. Aab1, …, M. Boháčová2, J. Chudoba2, J. Ebr2, D. Mandát2, P. Nečesal2, M. Palatka2, M. Pech2, M. Prouza2, J. Řídký2, P. Schovánek2, P. Trávníček2, J. Vicha2, et al.)

The surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60 deg. and different energies of the primary particle. From these distributions we define Xμmax as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of Xμmax as a useful observable to infer the mass composition of ultrahigh-energy cosmic rays. Likewise, we assess its ability to constrain hadronic interaction models.

Real reconstructed Muon Production Depth distributions for three different events at three different energies: E = (91±3)  EeV (top), E = (33±1)  EeV (middle), and E = (20±1)  EeV (bottom).

1Universität Siegen, Siegen, Germany
2Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic

Copyright © 2008-2014, Fyzikální ústav AV ČR, v. v. i.