Neutrino Burst Monitoring in Our Galaxy

Journal of Experimental and Theoretical Physics - Baksan underground scintillation telescope (BUST) operates under the program of neutrino burst search since the middle of 1980. We report the...     

Study of the hadronic component of extensive air showers at the Carpet-2 EAS array

A method for the detection of hadrons with a muon detector at the Carpet-2 EAS array (Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences) has been described. Events induced by cosmic-ray hadrons have a signature that makes it possible to reliably distinguish them from muons. The characteristics of the hadronic component of extensive air showers with N _e ≥ 10⁵ have been presented.     

The search for ultrashort bursts of cosmic ray intensity on the Andyrchi air shower array

A new data acquisition system that makes it possible to measure the count rate of each detector of the Andyrchi air shower array every millisecond is described. This new detection system allows us to search for ultrashort bursts of cosmic ray intensity when operating the array in the single-component detection mode. The method of data acquisition and analysis is discussed.     

Temperature effects in high-energy muon fluxes and the problem of reconstructing the atmospheric temperature profile

The temperature dependence of the high-energy muon flux is investigated using the experimental data from the Baksan Underground Scintillation Telescope. A method for reconstructing the atmosphere temperature profile is discussed.     

Temperature variations in the flux of high-energy muons

The flux of high-energy muons (threshold energy, 220 GeV) as a function of atmospheric temperature is measured using data from the Baksan Underground Scintillation Telescope (BUST). The temperature was measured every 12 h by radiosonde at different levels of observations. The results from studying the correlation coefficient between the counting rate of muons and the temperature of the atmosphere at different altitudes are presented.     

Sharp large deviations for some hyperbolic flows

We prove a sharp large deviation principle concerning intervals shrinking with sub-exponential speed for certain models involving the Poincaré map related to a Markov family for an Axiom A flow restricted to a basic set satisfying some additional regularity assumptions.     

Investigation of the spectrum of high-energy muons by the method of multiple interactions on the basis of data from the Baksan underground scintillation telescope

Experimental data obtained with the aid of the Baksan underground scintillation telescope over a long period of its operation are analyzed with the aim of searches for an excess flux of ultrahigh-energy (≥100 TeV)muons. The multiple-interaction method, which is based on the ideas of the pair-meter technique, is used to analyze the energy spectrum of the muons. The phenomenological parameters of this method and its sensitivity to the shape of the spectrum are discussed. The experimental distributions are compared with the results of calculations for various versions of the muon spectrum. The possibility of separating ultrahigh-energy muons that fly in the vicinity of the axis of extensive air showers is assessed on the basis of the integrated number of recorded and simulated events featuring large energy depositions.     

The Carpet-3 experiment to search for diffuse gamma rays with energies of more than 100 TeV

An experiment for measuring the flux of cosmic diffuse gamma rays with energies above 100 TeV (the Carpet-3 air shower array) is now being prepared at the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. The preparations entail a substantial increase of the areas of both the muon detector and the surface air shower array. The experiment’s sensitivity to showers generated by primary gamma rays is estimated for different configurations of the array. In addition, preliminary estimates of the upper limit on the flux of diffuse gamma rays with energies higher than 1.3 PeV, derived using experimental data from the old Carpet-2 array, are presented for a net exposure time of 9.2 years.     

Searching for neutrino bursts in the galaxy: 36 years of exposure

The Baksan Underground Scintillation Telescope has operated within the program of searching for neutrino bursts since the mid-1980s. We present the current status of the experiment and some results related to the investigation of background events and the stability of facility operation. Over the period from June 30, 1980, to December 31, 2016, the pure observation time was 31.27 years. No neutrino burst candidate event from the explosion of a core-collapse supernova in the Galaxy was recorded in this time. This sets an upper bound of 0.074 yr^–1 on the mean frequency of gravitational stellar collapses in the Galaxy at a 90% confidence level.     

Carpet-2 Search for PeV Gamma Rays Associated with IceCube High-Energy Neutrino Events

JETP Letters - Carpet-2 is an air-shower array at Baksan Valley, Russia, equipped with a large-area (175 m2) muon detector, which makes it possible to separate primary photons from hadrons. We...