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Using data of the Baksan Underground Scintillation Telescope (BUST) we have made a search for muon neutrinos and antineutrinos with energies above 1 GeV coinciding with the gravitational wave event GW170817 that was recorded on August 17, 2017 by the Advanced LIGO and Advanced Virgo observatories. This is a first detection of the new type of events occurring as a result of a merger of two neutron stars in a binary system. A short gamma-ray burst GRB170817A accompanying this event is an evidence of particle acceleration in the source whose precise position was determined by detection of the subsequent optical signal. No neutrino signals were found with the BUST in the interval $\pm 500$ s around the moment of the gravitational wave event GW170817, as well as during the next 14 days. The upper limits on integral fluxes of muon neutrino and antineutrino from the source are derived., Comment: Submitted to JETP Letters more...

The experiment on recording neutrino bursts operates since the mid-1980. As the target, we use two parts of the facility with the total mass of 240 tons. The current status of the experiment and some results related to the investigation of background events and the stability of facility operation are presented. Over the period of June 30, 1980 to December 31, 2018, the actual observational time is 33.02 years. No candidate for the stellar core collapse has been detected during the observation period. An upper bound of the mean frequency of core collapse supernovae in our Galaxy is 0.070 year$^{-1}$ (90\% CL)., Comment: Submitted to Astropart.Phys more...

A new method of determining Primary Cosmic Ray mass composition is proposed. The method is based on quasi-localization of the integral equation for the Extensive Air Showers spectrum versus the total number of high energy muons ($E_\mu \geqslant 235$ GeV) and an expansion of the experimentally measured spectrum in spectra of five group of primary nuclei. The cosmic ray mass composition is established in the energy region $10^{14}-10^{16}$ eV. In the region $10^{15}-10^{16}$ eV our analysis points to a lightening of the mass composition from $p+\alpha \simeq 0.54,\ \langle \ln A \rangle \simeq 1.97$ to $p+\alpha \simeq 0.69,\ \langle \ln A \rangle\simeq 1.56$., Comment: A few days ago we have been informed by an author of the paper Voevodsky A.V., Petkov V.B., Semenov A.M. et al., Rus.J. Izvestiya of RAS, ser.phys., v.58, N 12, p.127, (1994) that the muon multiplicity spectrum obtained in the aforementioned paper by Voevodsky et al is wrong. We used this spectrum as input data in our work. Therefore we have to withdraw the preprint 1311.0970 more...

The method of a determination of the Primary Cosmic Ray mass composition is presented. Data processing is based on the theoretical model representing the integral muon multiplicity spectrum as the superposition of the spectra corresponding to different kinds of primary nuclei. The method consists of two stages. At the first stage, the permissible intervals of primary nuclei fractions f_i are determined on the base of the EAS spectrum vs the total number of muons (E_mu > 235 GeV). At the second stage, the permissible intervals of f_i are narrowed by fitting procedure. We use the experimental data on high multiplicity muon events (n_mu > 114) collected at the Baksan underground scintillation telescope. Within the framework of three components (protons, helium and heavy nuclei), the mass composition in the region 10^15-10^16 eV has been defined: f_p = 0.235 +- 0.02, f_He = 0.290 +- 0.02$, f_H = 0.475 +- 0.03., Comment: 14 pages, 6 figures more...

Differential and integral energy spectra of cosmic ray muons in the energy range from several TeV to ~ 1 PeV obtained by means of the analysis of multiple interactions of muons (pair meter technique) in the Baksan underground scintillation telescope (BUST) are presented. The results are compared with preceding BUST data on muon energy spectrum based on electromagnetic cascade shower measurements and depth-intensity curve analysis, with calculations for different muon spectrum models, and also with data of other experiments., Comment: minor revision of the text and some of the pictures, 13 pages, 11 figures more...

Current status and results of the experiment on recording neutrino bursts are presented. The observation time (since 1980) is 24.7 years. The upper bound of collapse frequency in our Galaxy is 0.093 $y^{-1}$ (90% CL)., Comment: 3 pages, 2 figures. Presented at the 31 International Cosmic Ray Conference, Lodz, Poland, July 7-15, 2009 more...

Results of processing experimental data on charm production in hadron-hadron interactions are presented. The analysis is carried out within the frame of phenomenological model of diffraction production and quark statistics based on additive quark model (AQM). In low energy region sqrt s = 20 - 40GeV, the cross sections si_ {pN to c bar cX} (s), si_ {pi N to c bar cX} (s) are fitted by logarithmic function with the parameters connected by relationship of AQM. At collider energies 200, 540, 900, 1800 GeV, the values of si_{bar pp to c bar cX} (s) were obtained by a quark statistics method from the data on diffraction dissociation. It is established, that logarithmic function with universal numerical parameters describes the whole set of low-energy and high-energy data with high accuracy. The expected values of cross sections are si_{pp to c bar cX} = 250 pm 40 mu b and 355 pm 57 mu b at TEVATRON energy sqrt {s} = 1.96 TeV and LHC energy sqrt {s} = 14 TeV accordingly. Opportunities of use of the obtained results for calibration of a flux of "prompt" muons in high-energy component of cosmic rays are discussed., Comment: 7 pages, 3 figures more...