Speaker
Prof.
Igor Yashin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Description
An excess of multi-muon events in comparison with simulations performed in frame of widely used hadron interaction models was found in several cosmic ray experiments at very- and ultra-high energies of primary particles. In order to solve this so-called ‘muon puzzle’, investigations of the energy characteristics of EAS muon component are required. A possible approach to such investigations is the measurement of the energy deposit of EAS muons in the detector material: the appearance of an excessive fraction of very high-energy muons should be reflected in the dependence of the energy deposit on the energy of primary particles. The experiment on the study of the energy deposit of muon bundles is being conducted at the NEVOD-DECOR experimental complex. As a measure of the energy deposit, the sum of the responses of quasi-spherical modules of the Cherenkov calorimeter NEVOD is used. The local muon density in the event and the muon bundle arrival direction are estimated from the data of coordinate-tracking detector DECOR. Registration of inclined muon bundles of different multiplicities at various zenith angles allows to evaluate primary particle energies and to explore the energy interval from ~ 10^16 to 10^18 eV. Experimental data accumulated from May 2012 to April 2015 (about 17,000 hours live observation time) have been analyzed and compared with CORSIKA based simulations. It is found that the average specific energy deposit (i.e., the calorimeter response normalized to the local muon density in the events) appreciably increases with zenith angle, thus reflecting the increase of the muon energy in the bundles near horizon. An evidence for an increase of the energy deposit at primary energies above 10^17 eV is seen in the measured dependence of the specific energy deposit on the muon density. Possible methodical and physical reasons of such anomalous behavior are analyzed.
| Registration number following "ICRC2015-I/" | 53 |
|---|---|
| Collaboration | -- not specified -- |
Primary author
Prof.
Igor Yashin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Co-authors
Dr
Alexey Bogdanov
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Prof.
Anatoly Petrukhin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Mr
Dmitry Chernov
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Mrs
Ekaterina Kovylyaeva
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Ms
Evgeniya Romanenkova
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Dr
Giampaolo Mannocchi
(Consiglio Nazionale delle Ricerche (IT))
Dr
Gian Carlo Trinchero
(Consiglio Nazionale delle Ricerche (IT))
Dr
Konstantin Kompaniets
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Mr
Lev Dushkin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Dr
Natalia Barbashina
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Prof.
Oscar Saavedra
(Torino University)
Dr
Rostislav Kokoulin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Dr
Semen Khokhlov
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Mr
Vasily Khomyakov
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Mr
Victor Kindin
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
Dr
Victor Shutenko
(National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
