The term “muon puzzle” was formulated at International Symposium on Future Directions in UHECR Physics in CERN 13–16 February 2012. In this paper, various aspects of muon puzzle are considered. ...Obtained experimental data can be divided into two types: muon bundle excess compared to simulations which is increasing with the increase of primary particle energy, and the excess of very-high-energy muons (>100TeV) in the muon energy spectrum. One of the possible (and realistic) solutions of the muon puzzle is the hypothesis about production of blobs of quark-gluon matter with large orbital momentum in nucleus–nucleus interactions at energies more than several PeV. Possibilities of the check of this hypothesis are discussed.
There was a lot of puzzles in the history of the discovery and investigations of the muon itself and the muon component of cosmic rays. The last of them is an excess of high-multiplicity muon groups ...that grows with increasing energy of primary cosmic rays and which is detected in various experiments. An excess of muons that have ultrahigh energies (above 100 TeV) is the second aspect of the muon puzzle. Various approaches to solving the muon puzzle that are associated with measuring the energy features of the muon component of cosmic rays are considered.
A possibility to implement in well-known program CORSIKA user-made changes connected with heavy particles’ production in nucleus–nucleus interactions is considered. Program PYTHIA8.3 and the ...developed interface between it and CORSIKA are used for that. It is shown that implementation of PYTHIA leads to the increase in the number of muons at the ground level (
) and electrons (up to 10
). At the same time, the introduction of the top quark in first nucleus–nucleus collisions does not result in the increase of the number of particles in extensive air showers at the ground level.
The term "Megascience" appeared relatively not long time ago and has no distinct definition. Intuitively, this term is understood as something big and certainly expensive, i.e. a concept of ..."Megascience" is replaced by a concept of "Megamoney". In this paper, the unique scientific facility "NEVOD Experimental complex" (USF NEVOD), which satisfies all requirements to Megascience facilities, is described. USF NEVOD provides conduction of basic and applied investigations of cosmic rays in the record energy interval 109 − 1019 eV. Obtained scientific results are considered, and their comparison with other, larger scale detectors is discussed. This comparison shows the advantage of original approach used in the NEVOD complex compared to traditional methods of investigations. Taking into account the location of USF NEVOD in the University, the Scientific and Educational Center was organized on its bases. This allows solve two important tasks: to provide permanent operation of USF NEVOD by envolving students and to ensure their training in frame of real scientific experimental investigations. Some other questions of development and functioning of unique scientific facilities are considered, too.
Muon Puzzle in Cosmic Rays Petrukhin, A. A.
Moscow University physics bulletin,
04/2022, Letnik:
77, Številka:
2
Journal Article
Recenzirano
Short history and modern status of muon puzzle in cosmic rays of very high energies are described. Possible reasons of muon puzzle appearance are discussed. Some experimental ways of muon puzzle ...solution are considered. One of them is the measurement of energy characteristics of muons, which give the contribution to the observed excess of muon bundles at very high energies. Preliminary results of measurements of muon bundle energy deposit at large zenith angles are analysed.
Abstract
In this work, we use muon bundles, which are formed in extensive air showers and detected at the ground level, as a tool for searching for anisotropy in high-energy cosmic rays. Such choice ...is explained by the penetrating ability of muons that allows them to retain the direction of primary particles with good accuracy. In 2012–2022, we performed long-term muon-bundle detection with the coordinate-tracking detector DECOR, which is a part of the Experimental Complex NEVOD (MEPhI, Moscow). To search for cosmic-ray anisotropy, muon bundles arriving at zenith angles in the range from 15° to 75° in the local coordinate system are used. During the entire period of data taking, about 14 million of such events have been accumulated. In this paper, we describe some methods developed in the Experimental Complex NEVOD and implemented in our research, including: the method for compensating for the influence of meteorological conditions on the intensity of muon bundles at the Earth’s surface, the method for accounting for the design features of the detector and the inhomogeneity of the detection efficiency for different directions, as well as the method for estimating the primary energies of cosmic rays. Here we present the results of the search for the dipole anisotropy of cosmic rays with energies in the PeV region and also compare them with the results obtained at other scientific facilities.
In autumn 2018, the Working group on Hadronic Interactions and Shower Physics (WHISP) had compiled the results of various experiments in which cosmic ray muon bundles were registered. In some ...experiments, an excess of the number of muons is observed in comparison with Monte Carlo simulations with different hadronic interaction models at energies of primary nuclei above 10 PeV. However, not all experiments showed an excess. We present a review of methods for detecting muon bundles by various installations which data were investigated by the WHISP group.
Abstract
In the classification of the Ministry of Science and Higher Education in the National Project “Nauka” (2018), the concept of MegaScience is the name of a class of unique scientific ...installations, and in general terms, these are large expensive international scientific and research complexes for solution of actual scientific problems. It is emphasized that world-class breakthrough research is impossible within the framework of one university or organization, without attracting multi-billion budgets. However, the practice of MEPhI shows that it is possible to construct the unique scientific installations and to achieve results comparable to the largest international projects within a university in cooperation with other Russian and foreign organizations.
Muonography is an analog of other similar concepts such as X-ray radiography, electronography, neutronography, etc. based on the detection of penetrating radiation whose interaction with objects ...under study causes changes in the initial flux of the used particles. Unlike all other ‘‘graphies’’ which use artificially formed particle fluxes, muons are of natural origin, since they are formed as a result of interactions of primary cosmic rays with the nuclei of atoms in the atmosphere. Since muons keep well the direction of motion of primary particles, muon flux allows studying of disturbances in the heliosphere and magnetosphere of the Earth which lead to variations of the flux of primary cosmic rays. Also, disturbances in the atmosphere directly affect the muon flux, thus it can be used to study atmospheric processes. The paper considers the main ideas of the method of muonography, as well as the examples of its application for studying various processes and phenomena in the heliosphere, magnetosphere and atmosphere of the Earth. In frames of the further development of muonography, we discuss the expediency of creating a network of muon hodoscopes in the Russian Federation for early detection of hazardous processes and phenomena over its territory.
We report a method for measuring complex coupling coefficients in a ring resonator of a laser gyroscope. It is shown how, using the results of the measurements, to predict the values of the lock-in ...threshold and nonlinear distortions of the scale factor of a laser gyroscope at the stage of assembly and adjustment of the ring resonator and, in particular, to detect the presence of dust particles in the working areas of the mirrors. The possibilities of using this method to optimize the process of sputtering multilayer mirrors of a laser gyroscope are discussed.
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