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A. Sabourov

Publications and source records attributed to A. Sabourov.

At least 19 recordsLinked to original sources
arXiv2024

Explanation to the article "On the calibration of ultra-high energy EASs at the Yakutsk array and Telescope Array"

We provide a detailed commentary on the energy calibration of the TA experiment described in our paper (arXiv:2404.16948 [astro-ph.HE]). That paper concludes that the TA energy estimation, which is tied to optical measurements, might be incorrect. A response from members of the TA Collaboration (arXiv:2407.12892 [astro-ph.HE]) states that this conclusion is wrong and "stems from a misinterpretation and an incorrect application of the TA energy deposit formula". Here we demonstrate that our formula for energy deposit is not in fact a rescaled modification of the TA equation, but follows from description of the processes occurring during the passage of charged particles through 1.2 cm thick scintillator. Our estimation of the TA detector response implies the correctness of the cosmic ray spectrum derived from readings of surface detectors of the array.

astro-ph.HE↗
arXiv2024

Estimation of the composition of ultra-high energy cosmic rays using the muon correlation method based on Yakutsk EAS array data

In this article a new method is proposed for estimating the mass composition of cosmic rays in individual events with energies above $1.25 \times 10^{19}$ eV. It is based on a joint analysis of experimental data and simulation results obtained using the QGSJet-II.04 model for muons with threshold energy $E_μ = 1.0 \times \cosθ$ GeV in air showers with zenith angles up to 60 degrees. The data from ground-based and underground scintillation detectors of the Yakutsk EAS array were used. Separate groups of nuclei and other primary particles were found.

astro-ph.HE↗
arXiv2016

Search for Neutrino Generated Air Shower Candidates with Energy More than 5$\cdot$10$^{18}$ eV and Zenith Angle $θ$ $\geq$ 50$^\circ$

Neutrino air showers can be formed in any part of the atmosphere passing a long was in the matter due to its physical properties. In general, air showers produced by neutrinos are highly inclined and formed near the ground level, i.e. young showers. Therefore, one should expect a large number of peaks in the signal of such air showers [1, 2, 3]. The goal of our work is to search for air shower candidates produced by neutrino. For this purposes, we analyzed large amount of data from scintillation detectors with different area and energy thresholds [1, 2]. Preliminary analysis of Yakutsk array data indicated the absence of air shower produced by neutrino, but it does not mean that such air showers does not exist. It is going to need a further analysis of highly inclined showers. In order to do that improved methodology for recording and processing of air showers required.

astro-ph.HE↗
arXiv2014

Mass composition of cosmic rays with energy above 10**17 eV according to surface detectors of the Yakutsk EAS array

We discuss the lateral distribution of charged particles in extensive air showers with energy above $10^{17}$ eV measured by surface scintillation detectors of Yakutsk EAS array. The analysis covers the data obtained during the period from 1977 to 2013. Experimental values are compared to theoretical predictions obtained with the use of CORSIKA code within frameworks of different hadron interaction models. The best agreement between theory and experiment is observed for QGSJet01 and QGSJet-II-04 models. A change in the cosmic ray mass composition towards proton is observed in the energy range $(1-20) \times 10^{17}$ eV.

astro-ph.HE↗
arXiv2014

Revision of the energy calibration of the Yakutsk EAS array

Responses of surface and underground scintillation detectors of Yakutsk array are calculated for showers initiated by primary particles with energy E0>=1.0E17 eV within the frameworks of QGSJet01 QGSIIJet-II-04, SIBYLL-2.1 and EPOS-LHC hadron interaction models. A new estimation of E0 is obtained with the use of various methods. The resulting energy is lower compared to the obtained with earlier method by factor ~1.33.

astro-ph.HE↗
arXiv2014

An improved measurement of the 2νββ half-life of Xe-136 with EXO-200

We report on an improved measurement of the 2νββ half-life of Xe-136 performed by EXO-200. The use of a large and homogeneous time projection chamber allows for the precise estimate of the fiducial mass used for the measurement, resulting in a small systematic uncertainty. We also discuss in detail the data analysis methods used for double-beta decay searches with EXO-200, while emphasizing those directly related to the present measurement. The Xe-136 2νββ half-life is found to be 2.165 +- 0.016 (stat) +- 0.059 (sys) x 10^21 years. This is the most precisely measured half-life of any 2νββ decay to date.

nucl-ex↗
arXiv2013

Variations of the cosmic ray composition at energy above 0.1 EeV as observed by muon detectors of Yakutsk array

The lateral distribution of muons with ~1.0x\sec(θ) GeV in extensive air showers within ~10^{17}-10^{19} eV energy region obtained during different observational periods from November 1987 to June 2013 has been analyzed. Experimental data have been compared to predictions of various hadron interaction models. The best agreement is observed with QGSJETII-04. Until 1996, the mass composition of cosmic rays with energy below 2x10^{18} eV was significantly lighter than in later periods.

astro-ph.HE↗
arXiv2013

The nature of pulses delayed by 5 mcs in scintillation detectors from showers with the energy above 1E17 eV

Here we consider EAS events with energy above 1E17 eV with recorded pulses delayed by t>=5 mcs in scintillation detectors with different thresholds: 10, 5 and 1.8 MeV. In order to identify pulses from electrons, muons and neutrons, experimental data were compared to computational results performed within the framework of QGSJET01d model. Preliminary, one may speculate of registration of low-energy electrons arisen from moderation of neutrons in a detector or a medium surrounding a detector or in the snow cover and frozen crust (albedo particles). The fact that such pulses were registered mostly in low-threshold detectors confirms this hypothesis.

astro-ph.IM↗
arXiv2013

Muons in EAS with E>=10^17eV according to the data from Yakutsk array

The lateral distribution of muons with threshold energy e ~ 1*sec(theta) GeV have been studied in showers with energy E>=10^17 eV. The data considered in the analysis have been collected from November 2011 to June 2013. Experimental values are compared to predictions obtained with the use of CORSIKA code within the framework of various hadron interaction models. The best agreement between experiment and theory is observed for QGSJETII-04 model. At E~10^17 eV it complies to a mixed cosmic ray composition with the mean atomic number ~3.0+/-0.5. At E>= 4*10^17 eV the composition varies around the value ~0.5.

astro-ph.HE↗
arXiv2013

Air Shower Simulation and Hadronic Interactions

The aim of this report of the Working Group on Hadronic Interactions and Air Shower Simulation is to give an overview of the status of the field, emphasizing open questions and a comparison of relevant results of the different experiments. It is shown that an approximate overall understanding of extensive air showers and the corresponding hadronic interactions has been reached. The simulations provide a qualitative description of the bulk of the air shower observables. Discrepancies are however found when the correlation between measurements of the longitudinal shower profile are compared to that of the lateral particle distributions at ground. The report concludes with a list of important problems that should be addressed to make progress in understanding hadronic interactions and, hence, improve the reliability of air shower simulations.

astro-ph.HE↗
arXiv2013

Ba-ion extraction from a high pressure Xe gas for double-beta decay studies with EXO

An experimental setup is being developed to extract Ba ions from a high-pressure Xe gas environment. It aims to transport Ba ions from 10 bar Xe to vacuum conditions. The setup utilizes a converging-diverging nozzle in combination with a radio-frequency (RF) funnel to move Ba ions into vacuum through the pressure drop of several orders of magnitude. This technique is intended to be used in a future multi-ton detector investigating double-beta decay in $^{136}$Xe. Efficient extraction and detection of Ba ions, the decay product of Xe, would allow for a background-free measurement of the $^{136}$Xe double-beta decay.

physics.ins-det↗
arXiv2012

Search for Neutrinoless Double-Beta Decay in $^{136}$Xe with EXO-200

We report on a search for neutrinoless double-beta decay of $^{136}$Xe with EXO-200. No signal is observed for an exposure of 32.5 kg-yr, with a background of ~1.5 x 10^{-3} /(kg yr keV) in the $\pm 1σ$ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay $T_{1/2}^{0νββ}$($^{136}$Xe) > 1.6 x 10$^{25}$ yr (90% CL), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.

hep-ex↗
arXiv2012

The EXO-200 detector, part I: Detector design and construction

EXO-200 is an experiment designed to search for double beta decay of $^{136}$Xe with a single-phase, liquid xenon detector. It uses an active mass of 110 kg of xenon enriched to 80.6% in the isotope 136 in an ultra-low background time projection chamber capable of simultaneous detection of ionization and scintillation. This paper describes the EXO-200 detector with particular attention to the most innovative aspects of the design that revolve around the reduction of backgrounds, the efficient use of the expensive isotopically enriched xenon, and the optimization of the energy resolution in a relatively large volume.

physics.ins-det↗
arXiv2011

Spectrum and mass composition of cosmic rays in the energy range 10^15-10^18 eV derived from the Yakutsk array data

A spectrum of cosmic rays within energy range 10^15 - 3x10^17 eV was derived from the data of the small Cherenkov setup, which is a part of the Yakutsk complex EAS array. In this, work a new series of observation is covered. These observations lasted from 2000 till 2010 and resulted in increased number of registered events within interval 10^16 - 10^18 eV, which in turn made it possible to reproduce cosmic ray spectrum in this energy domain with better precision. A sign of a thin structure is observed in the shape of the spectrum. It could be related to the escape of heavy nuclei from our Galaxy. Cosmic ray mass composition was obtained for the energy region 10^16 - 10^18 eV. A joint analysis of spectrum and mass composition of cosmic rays was performed. Obtained results are considered in the context of theoretical computations that were performed with the use of hypothesis of galactic and meta-galactic origin of cosmic rays.

astro-ph.HE↗
arXiv2011

Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200

We report the observation of two-neutrino double-beta decay in Xe-136 with T_1/2 = 2.11 +- 0.04 (stat.) +- 0.21 (sys.) x 10^21 yr. This second order process, predicted by the Standard Model, has been observed for several nuclei but not for Xe-136. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrino-less double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.

nucl-ex↗
arXiv2011

Xenon purity analysis for EXO-200 via mass spectrometry

We describe purity measurements of the natural and enriched xenon stockpiles used by the EXO-200 double beta decay experiment based on a mass spectrometry technique. The sensitivity of the spectrometer is enhanced by several orders of magnitude by the presence of a liquid nitrogen cold trap, and many impurity species of interest can be detected at the level of one part-per-billion or better. We have used the technique to screen the EXO-200 xenon before, during, and after its use in our detector, and these measurements have proven useful. This is the first application of the cold trap mass spectrometry technique to an operating physics experiment.

physics.ins-det↗
arXiv2010

The Relation Between Charged Particles and Muons With Threshold Energy 1 GeV in Extensive Air Showers Registered at the Yakutsk EAS Array

Characteristics of the muon component in EAS are analyzed together with their fluctuations. The aim of this analysis -- a comparison of experimental data with computational results obtained within frameworks of various hadron interaction models for protons and iron nuclei and an estimation of cosmic ray mass composition in the ultra-high energy region.

astro-ph.HE↗