Oct 8 – 12, 2018
Ecole Supérieure de Chimie, Paris
Europe/Paris timezone

Study of muons from ultrahigh energy cosmic ray air showers measured with the Telescope Array experiment

Oct 10, 2018, 4:06 PM
Main Hall (Ecole Supérieure de Chimie)

Main Hall

Ecole Supérieure de Chimie

Chimie Paris Tech


Dr Ryuji Takeishi (Sungkyunkwan University, South Korea)


One of the uncertainties in ultrahigh energy cosmic ray (UHECR) observation derives from the hadronic interaction model used for air shower Monte-Carlo (MC) simulations. One may test the hadronic interaction models by comparing the measured number of muons observed at the ground from UHECR induced air showers with the MC prediction.
The Telescope Array (TA) is the largest experiment in the northern hemisphere observing UHECR in Utah, USA. It aims to reveal the origin of UHECRs by studying the energy spectrum, mass composition and anisotropy of cosmic rays by utilizing an array of surface detectors (SDs) and fluorescence detectors. We studied muon densities in the UHE extensive air showers by analyzing the signal of TA SD stations for highly inclined showers. On condition that the muons contribute about 65% of the total signal, the number of particles from air showers is typically 1.88 ± 0.08 (stat.) ± 0.42 (syst.) times larger than the MC prediction with the QGSJET II-03 model for protons. The same feature was also obtained for other hadronic models, such as QGSJET II-04. In this presentation, we report the method and the result of the study of muons from UHECR air showers with the TA data.

Primary author

Dr Ryuji Takeishi (Sungkyunkwan University, South Korea)


Presentation materials