Study of the energy deposit of muon bundles in the NEVOD detector

A.G Bogdanov,V.V Shutenko,S.S Khokhlov,I.I Yashin,E.A Kovylyaeva,A.A Petrukhin,O Saavedra,V.A Khomyakov,R.P Kokoulin,G Trinchero,G Mannocchi,L.I Dushkin,V.V Kindin,D Berge,A De Roeck,M Mangano,B Pattison

doi:10.1051/epjconf/20159906004

Abstract

In several cosmic ray experiments, an excess of multi-muon events in comparison with calculations performed in frame of the widely used hadron interaction models was found. In order to solve this puzzle, investigations of muon energy characteristics in EAS are required. An experiment on the measurement of the energy deposit of muon bundles in water has been started with the NEVOD-DECOR experimental complex. The results of the analysis of the first experimental data are discussed. It has been found that the average specific energy deposit in the Cherenkov calorimeter appreciably increases with zenith angle, thus reflecting the increase of the mean muon energy in the bundles. A possible evidence for an increase of the energy deposit at primary energies above 10 17 eV is observed.

Highlights

In several cosmic ray experiments at very- and ultra-high energies of primary cosmic ray particles [1,2,3,4,5] an excess of muons in comparison with simulation performed within the framework of commonly used hadron interaction models has been revealed
The number of Cherenkov photons, which are generated as a result of the passage of the muon through the water calorimeter, is approximately proportional to the total muon energy loss, and the average loss is almost linearly related to the energy (1)
Where Sdet is the total area of six DECOR SMs for a given direction, and β ≈ 2.1 is the integral slope of the local muon density spectrum (LMDS) in the considered muon density and zenith angle region [11]

Summary

Introduction

In several cosmic ray experiments at very- and ultra-high energies of primary cosmic ray particles [1,2,3,4,5] an excess of muons in comparison with simulation performed within the framework of commonly used hadron interaction models has been revealed. If the excess of high-energy muons appears in the bundles, it should be reflected in the dependence of the energy deposit E on the primary particle energy (see Fig. 1) [7]. Such experiment has been started at the NEVOD-DECOR complex (MEPhI, Russia) in 2012

Methods

Results

Conclusion