Energy loss measurements of inclined muon bundles in the Cherenkov water detector

R.P Kokoulin,A.G Bogdanov,G Trinchero,V.V Shutenko,E.A Yurina,A.A Petrukhin,O Saavedra,G Mannocchi,V.A Khomyakov,N.S Barbashina,S.S Khokhlov,V.V Kindin,I.I Yashin,K.G Kompaniets

doi:10.1051/epjconf/201920808006

R.P Kokoulin, A.G Bogdanov + Show 12 more

Open Access

https://doi.org/10.1051/epjconf/201920808006

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Abstract

An experiment on the measurements of the energy deposit of inclined cosmic ray muon bundles is being conducted at the experimental complex NEVOD (MEPhI). The complex includes the Cherenkov water calorimeter with a volume of 2000 m3 and the coordinate-tracking detector DECOR with a total area of 70 m2. The DECOR data are used to determine the local muon densities in the bundle events and their arrival directions, while the energy deposits (and hence the average muon energy loss) are evaluated from the Cherenkov calorimeter response. Average energy loss carries information about the mean muon energy in the bundles. The detection of the bundles in a wide range of muon multiplicities and zenith angles gives the opportunity to explore the energy range of primary cosmic ray particles from about 10 to 1000 PeV in the frame of a single experiment with a relatively small compact setup. Experimental results on the dependence of the muon bundle energy deposit on the zenith angle and the local muon density are presented and compared with expectations based on simulations of the EAS muon component with the CORSIKA code.

Highlights

In several cosmic ray experiments (e.g., [1, 2]) an excess of muons compared to simulations in extensive air showers (EAS) at ultra-high energies of primary particles has been revealed
The specific energy loss of muons in the region above hundreds GeV almost linearly increases with muon energy (−dE/dx ≈ a + bE), and the appearance of an excessive flux of high-energy muons should change the dependence of the average muon bundle energy deposit on the energy of the primary particle
The analysis showed that, to a first approximation, the total energy deposit in the Cherenkov water detector (CWD) is proportional to the local muon density

Summary

Introduction

In several cosmic ray experiments (e.g., [1, 2]) an excess of muons compared to simulations in extensive air showers (EAS) at ultra-high energies of primary particles has been revealed. A possible approach to such investigations is the measurement of the energy loss of muon bundles in the detector material. The specific energy loss of muons in the region above hundreds GeV almost linearly increases with muon energy (−dE/dx ≈ a + bE), and the appearance of an excessive flux of high-energy muons should change the dependence of the average muon bundle energy deposit on the energy of the primary particle. An experiment to investigate the energy deposit of inclined muon bundles was started at the experimental complex NEVOD in 2012.

Experimental setup and muon bundle data

Results and discussion

Conclusion