A postgraduate student of MEPhI has discovered the event with a group of large muons of a larhe multiplicity (124 muons) under a zenith angle 75 degrees during processing the experimental data, obtained in October by the coordinate-tracking detector DECOR and Cherenkov water calorimeter NEVOD.
"The primary particle entered the atmosphere about 80-100 km from Moscow. According to our estimates, the energy of the particle, that triggered the event, is ~7∙1018 eV, which corresponds to about 150 TeV in the centre-of-mass, that is 10 times higher than the maximum energy of the Large Hadron Collider at CERN," says the postgraduate student of the National Research Nuclear University MEPhI Ekaterina Yurina.
“There is an installation with an area of 3000 square kilometers in Argentina (Pierre Auger Observatory), built for the study of cosmic particles with such energies. An approach developed in MEPhI allows to record particles of such high energy, changing only the viewing angle,” commented the supervisor of E.A. Yurina, the chief researcher of SEC NEVOD, doctor of physical and mathematical sciences R.P. Kokoulin.
"The results of registration of muons groups on the other installations belong to much lower energies, as they detect particles coming from above. But our installation is aimed at particles coming almost horizontally. In this case, the main role is played not by the area of the installation, but the area covered by shower of particles, which can reach tens of square kilometers. And if the axis of the shower is at a great distance, it still goes to our detectors. This allows us to compete with the big installations where particles of ultrahigh energies are investigated by traditional methods. And we are very pleased that a particle with the record energy has been registered during the celebration of the 75th anniversary of the National Research Nuclear University MEPhI,” added Professor, the head of the SEC NEVOD Anatoly Petrukhin.
Coordinate-tracking detector DECOR placed in galleries around the Cherenkov water calorimeter NEVOD
Event with a group of 124 muons in the detector DECOR. On the left – Y-projection (azimuthal angles), on the right – the X-projection (zenith angles)
Geometric reconstruction of the event. Fine lines – the result of the reconstruction of muons tracks according to the DÉCOR detector; mugs – triggered photomultipliers of the NEVOD water calorimeter
