2021 год
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№ |
Название статьи |
Авторы |
Год |
Название журнала |
Краткая аннотация |
| 1 |
New measurements and analysis of elastic scattering of 13C by 9Be nuclei in a wide energy range |
Nassurlla M., Burtebayev N., Karakozov B.K., Sakuta S. B., Boztosun I., Amangeldi N., Morzabayev A. K., Yergaliuly G., Alimov D. K., Burtebayeva J., Nassurlla Maulen, Mauyey B., Kucuk Y., Hamada Sh., Khojayev R. |
2021 |
European Physical Journal A, Volume 57, Issue 7, July 2021, Номер статьи 231, Q2
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The angular distributions of 13C elastically scattered by 9Be nuclei were measured at ELab (13C) = 16.25 and 19.5 MeV. The measured angular distributions were analyzed via the optical model and the DWBA within the coupled reaction channels methods. In addition to this, the previously obtained data were reanalyzed at energies ELab = 22.75, 28.12, 36.15, 57.77 and 72.88 MeV. The aim of the study was to elucidate the role of the α-cluster transfer mechanism in the large-angle scattering. As a result of these calculations, the optimal parameters of the potentials and their energy dependence were obtained for 13C+9Be nuclear system. The data at the backward angles are fairly well reproduced. The spectroscopic amplitudes were extracted for the 13C → 9Be + α configuration at various energies. The results are compared with previously reported values. |
| 2 |
The spin-parities of the 13.35 MeV state and high-lying excited states around 20 MeV in 12C nucleus |
Demyanova A., Starastsin V., Ogloblin A., Danilov A., Dmitriev S., Trzaska W., Heikkinen P., Belyaeva T., Goncharov S., Maslov V., Sobolev Yu., GurovYu., Chernyshev B., Burtebaev N., Janseitov D., Khlebnikov S. |
2021 |
European Physics Journal A, Volume 57, Issue 6, June 2021 Номер статьи 204, Q2 https://doi.org/10.1140/epja/s10050-021-00515-7
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A study of the 11B(3He,d)12C reaction at incident 3He energy E lab = 25 MeV has been performed at the K-130 cyclotron at the University of Jyväskylä, Finland. Differential cross sections have been measured for the 13.35 MeV state and for the states with excitation energy around 20 MeV in 12C. The data were analyzed with the DWBA method. A tentative assignment, 4-, is given for the state at 13.35 MeV in a joint study of the reaction and inelastic scattering of α-particles with the energy of 110 MeV. For the state at 20.98 MeV, the possible spin-parity 3- and the isospin T = 0 are assigned for the first time. Our model description of the broad state at 21.6 MeV is consistent with the previous assignments of isospin T = 0 and spin-parity of 2+ or 3-. The excited state at 22.4 MeV may have possible spin-parities of either 6+ or 5-. The collected statistics was insufficient to solve this question. Rotational bands which can exist in 12C were presented. |
| 3 |
Approximate perfect fluid solutions with quadrupole moment
|
Medeu Abishev, Nurzada Beissen, Farida Belissarova, Kuantay Boshkayev, Aizhan Mansurova, Aray Muratkhan, Hernando Quevedo and Saken Toktarbay |
2021 |
International Journal of Modern Physics D, Q2 |
We investigate the interior Einstein's equations in the case of a static, axially symmetric, perfect fluid source. We present a particular line element that is specially suitable for the investigation of this type of interior gravitational fields. Assuming that the deviation from spherically symmetry is small, we linearize the corresponding line element and field equations and find several classes of vacuum and perfect fluid solutions. We find some particular approximate solutions by imposing appropriate matching conditions. |
| 4 |
The morphology of the X-ray afterglows and of the jetted GeV emission in long GRBs |
Ruffini R. , Moradi R. , Rueda J.A. , Li L. , Sahakyan N. , Chen Y.-C. ,Wang Y. , Aimuratov Y. , Becerra L. , Bianco C.L. , Cherubini C. , Filippi S. |
2021 |
Monthly Notices of the Royal Astronomical Society 504(4), Q1
|
We recall evidence that long gamma-ray bursts (GRBs) have binary progenitors and give new examples. Binary-driven hypernovae (BdHNe) consist of a carbon-oxygen core (COcore) and a neutron star (NS) companion. For binary periods ∼5 min, the COcore collapse originates the subclass BdHN I characterized by (1) an outstanding supernova (SN; the 'SN-rise'); (2) a black hole (BH), born from the NS collapse by SN matter accretion, leading to a GeV emission with luminosity $L_{\rm GeV} = A_{\rm GeV}\, t^{-\alpha _{\rm GeV}}$, observed only in some cases; and (3) a new NS (νNS), born from the SN, originating from the X-ray afterglow with $L_\mathrm{ X} = A_{\rm X}\, t^{-\alpha _{\rm X}}$, observed in all BdHN I. We record 378 sources and present for four prototype GRBs 130427A, 160509A, 180720B, and 190114C: (1) spectra, luminosities, SN-rise duration; (2) AX, αX = 1.48 ± 0.32, and (3) the νNS spin time evolution. We infer (i) AGeV, αGeV = 1.19 ± 0.04 and (ii) the BdHN I morphology from time-resolved spectral analysis, three-dimensional simulations, and the GeV emission presence/absence in 54 sources within the Fermi-Large Area Telescope boresight angle. For 25 sources, we give the integrated and time-varying GeV emission, 29 sources have no GeV emission detected and show X/gamma-ray flares previously inferred as observed along the binary plane. The 25/54 ratio implies the GeV radiation is emitted within a cone of half-opening angle ≈60° from the normal to the orbital plane. We deduce BH masses of 2.3-8.9 M⊙ and spin of 0.27-0.87 by explaining the GeV emission from the BH rotational energy extraction, while their time evolution validates the BH mass-energy formula. |
| 5 |
α-attractors from supersymmetry breaking |
Yermek Aldabergenov, Auttakit Chatrabhuti, Hiroshi Isono |
2021 |
European Physical Journal C 81 (2021) 2, 166, Q1 |
We construct new models of inflation and spontaneous supersymmetry breaking in de Sitter vacuum, with a single chiral superfield, where inflaton is the superpartner of the goldstino. Our approach is based on hyperbolic Kähler geometry, and a gauged (non-axionic) U(1) R symmetry rotating the chiral scalar field by a phase. The U(1) R gauge field combines with the angular component of the chiral scalar to form a massive vector, and single-field inflation is driven by the radial part of the scalar. We find that in a certain parameter range they can be approximated by simplest Starobinsky-like (E-model) α-attractors, thus predicting ns and r within 1 σ CMB constraints. Supersymmetry (and R-symmetry) is broken at a high scale with the gravitino mass m3 / 2≳ 10 14 GeV, and the fermionic sector also includes a heavy spin-1/2 field. In all the considered cases the inflaton is the lightest field of the model. |
| 6 |
Nilpotent superfields for broken abelian symmetries |
Yermek Aldabergenov, Auttakit Chatrabhuti, Hiroshi Isono |
2021 |
European Physical Journal C 81 (2021) 6, 523, Q1 |
We find new solutions to real cubic constraints on N= 1 chiral superfields transforming under global abelian symmetries. These solutions describe the low-energy dynamics of a goldstino interacting with an axion (both belonging to the same chiral superfield) with non-linearly realized supersymmetry. We show the relation between our model and the approach of Komargodski and Seiberg for describing goldstino-axion dynamics which uses orthogonal nilpotent superfields. |
| 7 |
Testing Primordial Black Holes as Dark Matter in Supergravity from Gravitational Waves
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Yermek Aldabergenov, Andrea Addazi, Sergei V. Ketov |
2021 |
Physics Letters B 814 (2021) 136069, Q1 https://doi.org/10.1016/j.physletb.2021.136069
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We explore the Gravitational Waves (GW) phenomenology of a simple class of supergravity models that can explain and unify inflation and Primordial Black Holes (PBH) as Dark Matter (DM). Our (modified) supergravity models naturally lead to a two-field attractor-type double inflation, whose first stage is driven by Starobinsky scalaron and the second stage is driven by another scalar belonging to a supergravity multiplet. The PBHs formation in our supergravity models is efficient, compatible with all observational constraints, and predicts a stochastic GW background. We compute the PBH-induced GW power spectrum and show that GW signals can be detected within the sensitivity curves of the future space-based GW interferometers such as LISA, DECIGO, TAIJI and TianQin projects, thus showing predictive power of supergravity in GW physics and their compatibility. |
| 8 |
Quasinormal modes in the field of a dyon-like dilatonic black hole. |
Malybayev A. N., Boshkayev K. A., Ivashchuk V. D. |
2021 |
The European Physical Journal C, 2021, Volume 81, Issue 5, article id.475, Q2
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Quasinormal modes of massless test scalar field in the background of gravitational field for a non-extremal dilatonic dyonic black hole are explored. The dyon-like black hole solution is considered in the gravitational 4d model involving two scalar fields and two 2-forms. It is governed by two 2-dimensional dilatonic coupling vectors λi obeying λi(λ1+ λ2) > 0 , i= 1 , 2. The first law of black hole thermodynamics is given and the Smarr relation is verified. Quasinormal modes for a massless scalar (test) field in the eikonal approximation are obtained and analysed. These modes depend upon a dimensionless parameter a (0 < a≤ 2) which is a function of λi. For limiting strong (a= + 0) and weak (a= 2) coupling cases, they coincide with the well-known results for the Schwarzschild and Reissner–Nordström solutions. It is shown that the Hod conjecture, connecting the damping rate and the Hawking temperature, is satisfied for 0 < a≤ 1 and all allowed values of parameters. |
| 9 |
Testing generalized logotropic models with cosmic growth |
Boshkayev K., Konysbayev T., Luongo O., Muccino M., Pace F. |
2021 |
Physical Review D, 2021, Volume 104, Issue 2, article id.023520, Q1 |
We check the dynamical and observational features of four typologies of logotropic dark energy models, leading to a thermodynamic cosmic speed up fueled by a single fluid that unifies dark energy and dark matter. We first present two principal Anton-Schmidt fluids where the Grüneisen parameter is free to vary and then fixed to the special value . We also investigate the pure logotropic model, corresponding to . Finally, we propose a new logotropic paradigm that works as a generalized logotropic fluid, in which we split the role of dark matter and baryons. We demonstrate that the logotropic paradigms may present drawbacks in perturbations, showing a negative adiabatic sound speed which make perturbations unstable. We thus underline which model is favored over the rest. The Anton-Schmidt model with is ruled out while the generalized logotropic fluid seems to be the most suitable one, albeit weakly disfavored than the model. To fix numerical constraints, we combine low- and higher-redshift domains through experimental fits based on Monte Carlo Markov Chain procedures, taking into account the most recent Pantheon supernovae Ia catalog, Hubble measurements, and data points based on the linear growth function for the large scale structures. We also consider two model selection criteria to infer the statistical significance of the four models under examination. We conclude there is a statistical advantage to handle the Anton-Schmidt fluid with the Grüneisen parameter free to vary and/or fixed to . The generalized logotropic fluid indicates suitable results, more statistically favored than the other models until the sound speed is positive, becoming unstable in perturbations elsewhere. We emphasize that the paradigm works statistically better than any kind of logotropic and generalized logotropic models, while the Chevallier-Polarski-Linder parametrization is statistically comparable with logotropic scenarios. Finally, we propose that generalizing the Grüneisen parameter by including the effects of temperature would guarantee the sound speed to be positive definite at all redshifts. |
| 10 |
Luminosity of accretion disks in compact objects with a quadrupole |
Boshkayev K., Konysbayev T., Kurmanov E., Luongo O., Malafarina D., Quevedo H. |
2021 |
Physical Review D, 2021, Volume 104, Issue 8, article id.084009, Q1 |
We consider the circular motion of test particles in the gravitational field of a static and axially symmetric compact object described by the metric. To this end, we calculate orbital parameters of test particles on accretion disks such as angular velocity (), total energy (), angular momentum (), and radius of the innermost stable circular orbit () as functions of the mass () and quadrupole () parameters of the source. The radiative flux, differential, and spectral luminosity of the accretion disk, which are quantities that can be experimentally measured, are then explored in detail. The obtained results are compared with the corresponding ones for the Schwarzschild and Kerr black holes in order to establish whether black holes may be distinguished from the metric via observations of the accretion disk’s spectrum. |
| 11 |
Effects of non-vanishing dark matter pressure in the Milky Way Galaxy |
Boshkayev K., Konysbayev T., Kurmanov E., Luongo O., Malafarina D., Mutalipova K., Zhumakhanova G. |
2021 |
Monthly Notices of the Royal Astronomical Society, 2021, Volume 508, Issue 1, pp.1543-1554, Q1 |
We consider the possibility that the Milky Way's dark matter halo possesses a non-vanishing equation of state. Consequently, we evaluate the contribution due to the speed of sound, assuming that the dark matter content of the galaxy behaves like a fluid with pressure. In particular, we model the dark matter distribution via an exponential sphere profile in the galactic core, and inner parts of the galaxy whereas we compare the exponential sphere with three widely used profiles for the halo, i.e. the Einasto, Burkert and Isothermal profile. For the galactic core, we also compare the effects due to a dark matter distribution without black hole with the case of a supermassive black hole in vacuum and show that present observations are unable to distinguish them. Finally we investigate the expected experimental signature provided by gravitational lensing due to the presence of dark matter in the core. |
| 12 |
Tracing Dark Energy History with Gamma-Ray Bursts |
M. Muccino, L. Izzo, O. Luongo, K. Boshkayev, L. Amati, M. Della Valle, G. B. Pisani, E. Zaninoni. |
2021 |
The Astrophysical Journal ( 2021), 908:181 (11pp), Q1 |
Observations of gamma-ray bursts up to z ∼ 9 are best suited to study the possible evolution of the universe equation of state at intermediate redshifts. We apply the Combo relation to a sample of 174 gamma-ray bursts to investigate possible evidence of evolving dark energy parameter w(z). We first build a gamma-ray burst Hubble's diagram and then we estimate the set (Ω m , ΩΛ) in the framework of flat and non-flat ΛCDM paradigm. We then get bounds over the wCDM model, where w is thought to evolve with redshift, adopting two priors over the Hubble constant in tension at 4.4σ, i.e., H 0 = (67.4 0.5) km s-1 Mpc-1 and H 0 = (74.03 1.42) km s-1 Mpc-1. We show our new sample provides tighter constraints on Ω m since at z ≤ 1.2 we see that w(z) agrees within 1σ with the standard value w = -1. The situation is the opposite at larger z, where gamma-ray bursts better fix w(z) that seems to deviate from w = -1 at 2σ and 4σ level, depending on the redshift bins. In particular, we investigate the w(z) evolution through a piecewise formulation over seven redshift intervals. From our fitting procedure we show that at z ≥ 1.2 the case w < -1 cannot be fully excluded, indicating that dark energy's influence is not negligible at larger z. We confirm the Combo relation as a powerful tool to investigate cosmological evolution of dark energy. Future space missions will significantly enrich the gamma-ray burst database even at smaller redshifts, improving de facto the results discussed in this paper. |
| 13 |
Traversable wormholes with vanishing sound speed in f(R) gravity |
Capozziello S., Luongo O., Mauro L. |
2021 |
European Physical Journal Plus, 2021, 136(2), 167, Q2 |
We derive exact traversable wormhole solutions in the framework of f(R) gravity with no exotic matter and with stable conditions over the geometric fluid entering the throat. For this purpose, we propose power-law f(R) models and two possible approaches for the shape function b(r)/r. The first approach makes use of an inverse power-law function, namely b(r) / r∼ r-1-β. The second one adopts Padé approximants, used to characterize the shape function in a model-independent way. We single out the P(0, 1) approximant where the fluid perturbations are negligible within the throat, if the sound speed vanishes at r= r. The former guarantees an overall stability of the geometrical fluid into the wormhole. Finally, we get suitable bounds over the parameters of the model for the above discussed cases. In conclusion, we find that small deviations from general relativity give stable solutions. |
| 14 |
Comparative role of the 7Li(n, γ) reaction in Big Bang nucleosynthesis |
Burkova, N.A., Dubovichenko, S.B., Dzhazairov-Kakhramanov, A.V., Nurakhmetova, S.Z. |
2021 |
Journal of Physics G: Nuclear and Particle Physics, 2021, V 48(4), 045201 (21pp), Q1 |
Within the framework of the modified potential cluster model with forbidden states and their classification according to Young diagrams, the possibility of describing experimental data on the total cross sections of the neutron radiative capture on 7Li is considered. It is shown that the model used and the methods for constructing potentials make it possible to correctly describe the behavior of experimental cross sections at energies of 1 meV to 1.5 MeV, where experimental data are available. Based on the calculated total cross sections up to 5 MeV, the reaction rate is calculated and its analytical approximation is carried out. Resonance structure of 7Li(n, γ)8Li cross section and its impact on the reaction rate is examined. It is shown that the 7Li(n, γ)8Li reaction dominates at T9 < 0.1 as opposed to the burning of 7Li in the 7Li(3H, n)9Be and 7Li(4He, γ)11B reactions, but comparable to (d, γ), (d, p), and (p, γ) at T9 ∼ 1. |
| 15 |
12B(n,γ)13B reaction as an alternative path to astrophysical synthesis of 13C isotope |
Dubovichenko, S.B., Burkova, N.A., Dzhazairov-Kakhramanov, A.V., Yertaiuly, A. |
2021 |
Nuclear Physics A, 2021, V 1011, P. 122197 (17pp), Q2 |
The total cross sections of the neutron radiative capture on 12B at astrophysical energies to the ground state of 13B, have been calculated in the energy range of 10−8 to 10 MeV within the framework of a modified potential cluster model with the classification of orbital states according to Young diagrams. Reaction rates in the temperature range of 0.01 to 10 T9, and their analytical parameterizations were obtained. The calculated rates of 12B(n,γ)13B excess the previous results obtained by other approaches by approximately to one order of magnitude. Cross sections and reaction rates of 12C(n,γ0+1+2+3)13C are calculated and compared to the n10B, n11B, n12B, and p12C reaction rates. It is proposed that the obtained rates of the 12B(n,γ)13B reaction may be suggested for the discussion of novel scenarios of stable isotope 13C synthesis when p-captures on 12C are not present. |
| 16 |
Scattering of α -particles and 3 He by 24 Mg nuclei at energies about 50–60 MeV |
Bahtiyar Sadykov, Timur Zholdybayev, Nassurlla Burtebayev, Bek Duisebayev, Maulen Nassurlla, Jumazya Burtebayeva , Marzhan Nassurlla , Stanislav Sakuta, Andrey Pan |
2021 |
European Physical Journal A Volume 57, Issue 4, April 2021, Номер статьи 130, Q1 |
Differential cross sections of elastic and inelastic scattering with excitation of states of the rotational band of the ground state of 24Mg were measured at an α-particle energy of 50.5 MeV and 3He 60 MeV. The angular distributions were analyzed using an optical model and a coupled channel method. A number of potentials with significantly different geometries are obtained, which describe well the elastic scattering at the measured angular range. The collective model was used in the calculations via the coupled channel method. In addition to the ground state, three low-lying states of 24Mg, 2+ (1.368 MeV), 4+ (4.122 MeV), and 4.238 MeV (2+), were included in the coupling scheme. The values of quadrupole (β2) and hexadecapole (β4) deformation parameters were extracted. According to the analysis of scattering of α-particles, they are 0.52 and 0.05. For 3He, they are 0.75 and 0.07, respectively. The extracted parameters correspond to the previously obtained values from the scattering of protons, deuterons and α-particles. |
| 17 |
Radiation resistance of single-mode optical fibres with view to in-reactor applications
|
Kashaykin P.F., Tomashuk A.L., Vasiliev S.A., Ignatyev A.D., Shaimerdenov A.A., Ponkratov Y.V., Kulsartov T.V., Kenzhin Y.A., Kh. Gizatulin S., Zholdybayev T.K., Chikhray Y.V., Semjonov S.L.
|
2021 |
Nuclear materials and energy, V.27, P.100981, Q2 |
Single-mode optical fibres (SMFs) are required for ITER in-vessel applications as transport fibres to deliver the signal at wavelength λ = 1.55 µm from/to optical fibre sensors. The paper describes the first comparison study of radiation resistance of six pure-silica-core SMFs of different manufacturers performed in the process of fission-reactor irradiation in the conditions corresponding to the whole ITER lifetime (fast-neutron fluence, flux, γ-dose and dose rate of up to 1.8·1020n/cm2, 1.08·1014n/(cm2·s), 2.32 GGy and 1.39 kGy/s, respectively, temperature of 170–190 °C and vacuum pumping). Polyimide- and acrylate-coated SMFs failed mechanically during the irradiation; therefore, only metal-coated fibres can be considered for the in-vessel applications. Induced optical loss in all three metal-coated SMFs (copper- and aluminum-coated ones) at the fast-neutron fluence of 1·1020n/cm2 was found to lie in the range ~1.5–4 dB/m, the lower value of this range allowing the employment of at least 10-m-long transport fibre lengths in the in-vessel applications, assuming the dynamic range of 30 dB. The temperature-dependent microbending optical loss in metal-coated SMFs is discussed, of which the contribution to the total induced loss may be comparable in value to the radiation-induced absorption of light. Neither radiation-induced luminescence, nor Cerenkov emission was detected in the SMFs in the near-infrared range. |
| 18 |
Linear energy density and the flux of an electric field in proca tubes |
V. Dzhunushaliev, V. Folomeev and Tlemisov, A |
2021 |
Symmetry, Volume 13, Issue 4, April 2021, Номер статьи 640, Q2 |
In this work, we study cylindrically symmetric solutions within SU(3) non-Abelian Proca theory coupled to a Higgs scalar field. The solutions describe tubes containing either the flux of a color electric field or the energy flux and momentum. It is shown that the existence of such tubes depends crucially on the presence of the Higgs field (there are no such solutions without this field). We examine the dependence of the integral characteristics (linear energy and momentum densities) on the values of the electromagnetic potentials at the center of the tube, as well as on the values of the coupling constant of the Higgs scalar field. The solutions obtained are topologically trivial and demonstrate the dual Meissner effect: the electric field is pushed out by the Higgs scalar field. © 2021 by the authors. |
| 19 |
Nonperturbative quantization approach for QED on the Hopf bundle |
V. Dzhunushaliev and V. Folomeev, |
2021 |
Universe 7, (2021) no.3, 65, Q2 |
We consider the Dirac equation and Maxwell’s electrodynamics in R × S3 spacetime, where a three-dimensional sphere is the Hopf bundle S3 → S2 . In both cases, discrete spectra of classical solutions are obtained. Based on the solutions obtained, the quantization of free, noninteracting Dirac and Maxwell fields is carried out. The method of nonperturbative quantization of interacting Dirac and Maxwell fields is suggested. The corresponding operator equations and the infinite set of the Schwinger–Dyson equations for Green’s functions is written down. We write a simplified set of equations describing some physical situations to illustrate the suggested scheme of nonper-turbative quantization. Additionally, we discuss the properties of quantum states and operators of interacting fields. © 2021 by the authors. |
| 20 |
Mass gap for a monopole interacting with a nonlinear spinor field |
Vladimir Dzhunushaliev, Nassurlla Burtebayev, Vladimir Folomeev, Jutta Kunz, Albina Serikbolova, and Abylaikhan Tlemisov |
2021 |
PHYSICAL REVIEW D 104, 056010 (2021), Q1 |
Within SU(2) Yang-Mills theory with a source of the non-Abelian gauge field in the form of a classical spinor field, we study the dependence of the mass gap on the coupling constant between the gauge and nonlinear spinor fields. It is shown that the total dimensionless energy of the monopole interacting with the nonlinear spinor fields depends only on the dimensionless coupling constant. |
| 21 |
Static and collapsing configurations supported by the spinor fluid |
Vladimir Dzhunushaliev and Vladimir Folomeev |
2021 |
Phys. Rev. D 103, 123017 (2021) - Published 15 June 2021, Q1 |
We study a gravitating spherically symmetric nonrelativistic configuration consisting of a spinor fluid whose effective equation of state is derived from a consideration of a limiting system supported by a massive nonlinear spinor field. For such a configuration, we find a two-parametric family of static regular solutions describing compact objects whose masses and sizes are determined by the central density of the spinor fluid and the mass of the spinor field. Using the similarity method, we consider a gravitational collapse of an initially uniform system consisting of the spinor fluid. We estimate the general characteristics of the collapse and show that a resulting nonuniform distribution of the fluid occurs that may serve as a core for the creation of equilibrium starlike configurations. |
| 22 |
Axially symmetric Proca-Higgs boson stars |
Vladimir Dzhunushaliev and Vladimir Folomeev |
2021 |
Phys. Rev. D 104, 104024 (2021) - Published 9 November 2021, Q` |
We consider strongly gravitating configurations consisting of coupled real Higgs scalar field and vector (Proca) field of mass μP. For such a system, we find static regular axially symmetric solutions describing asymptotically flat configurations which may be referred to as Proca-Higgs miniboson stars, since their total mass and spatial dimension are of order M2Pl/μP and μ−1P, respectively. The system possesses an axially symmetric dipole field and may be regarded as a Proca dipole. |
| 23 |
Masking singularities in Weyl gravity and Ricci flows |
V. Dzhunushaliev and V. Folomeev |
2021 |
Eur.Phys.J.C 81 (2021) 5, 387, Q1 |
Within vacuum Weyl gravity, we obtain a solution by which, using different choices of the conformal factor, we derive metrics describing (i) a bounce of the universe; (ii) toroidal and spherical wormholes; and (iii) a change in metric signature. It is demonstrated that singularities occurring in these systems are “masked”. We give a simple explanation of the possibility of masking the singularities within Weyl gravity. It is shown that in the first and third cases the three-dimensional metrics form Ricci flows. The question of the possible applicability of conformal Weyl gravity as some phenomenological theory in an approximate description of quantum gravity is discussed. |
| 24 |
Nonperturbative quantization approach for QED on the Hopf bundle |
V. Dzhunushaliev and V. Folomeev, |
2021 |
Universe 7, (2021) no.3, 65, Q2 |
We consider the Dirac equation and Maxwell’s electrodynamics in R × S3 spacetime, where a three-dimensional sphere is the Hopf bundle S3 → S2 . In both cases, discrete spectra of classical solutions are obtained. Based on the solutions obtained, the quantization of free, noninteracting Dirac and Maxwell fields is carried out. The method of nonperturbative quantization of interacting Dirac and Maxwell fields is suggested. The corresponding operator equations and the infinite set of the Schwinger–Dyson equations for Green’s functions is written down. We write a simplified set of equations describing some physical situations to illustrate the suggested scheme of nonper-turbative quantization. Additionally, we discuss the properties of quantum states and operators of interacting fields. |
| 25 |
Linear energy density and the flux of an electric field in proca tubes |
V. Dzhunushaliev, V. Folomeev and Tlemisov, A |
2021 |
Symmetry, Volume 13, Issue 4, April 2021, Номер статьи 640, Q2 |
In this work, we study cylindrically symmetric solutions within SU(3) non-Abelian Proca theory coupled to a Higgs scalar field. The solutions describe tubes containing either the flux of a color electric field or the energy flux and momentum. It is shown that the existence of such tubes depends crucially on the presence of the Higgs field (there are no such solutions without this field). We examine the dependence of the integral characteristics (linear energy and momentum densities) on the values of the electromagnetic potentials at the center of the tube, as well as on the values of the coupling constant of the Higgs scalar field. The solutions obtained are topologically trivial and demonstrate the dual Meissner effect: the electric field is pushed out by the Higgs scalar field. |
| 26 |
Solid-phase synthesis and study of the structural, optical, and photocatalytic properties of the ATiO3, A = Ca, Sr, Ba ceramic |
B.K.Karakozov, A.L.Kozlovskiy, D.M.Janseitov, M.V.Zdorovets |
2021 |
Journal of Materials Science: Materials in Electronics, V. 32, 24436–24445, Q2 |
This paper presents the results of a study of the structural, optical, and photocatalytic properties of ceramics based on ATiO3 titanates, A = Ca, Sr, Ba. Using the method of X-ray phase analysis, it was found that in the case of ceramics obtained from a mixture of BaCO3 and TiO2 after annealing, the structure is a mixture of two phases, rhombohedral BaTiO3 and impurity orthorhombic BaTi4O9. In the case of ceramics obtained from a mixture of CaCO3 and TiO2, the structure is a mixture of two phases of the orthorhombic phase and rutile TiO2. In the case of ceramics obtained from a mixture of SrCO3 and TiO2, the structure is a mixture of two phases of the SrTiO3 orthorhombic phase and the Ti2O5 orthorhombic phase. At the same time, all synthesized ceramics have a high crystallinity degree and order of the crystal structure. An analysis of the optical properties showed that the main changes are associated with the difference in the band gap, which is due to the presence of different phases in the structure of ceramics. Based on the results of photocatalytic reactions, the order of photocatalytic activity of the synthesized ceramics was determined: SrTO3/T2O5 > CaTO3/TO2 > BaTO3. |
| 27 |
Statistical analysis of object congestion in the geostationary region |
A. Serebryanskiy, Ch. Akniyazov, B. Demchenko, A. Komarov, Ch. Omarov, I. Reva, M. Krugov, V. Voropaev |
2021 |
Acta Astronautica
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The results of the statistical analysis of the number of near-miss events (NME) in the distance range from 1 km up to 200 km between objects on the geostationary orbits (GSO) for the period from 2011 to 2020, obtained from approximations based on catalogs of orbital elements, are presented. It was shown that the overall increase in the number of NMEs resulting from the filling of geostationary orbits due to new launches and the detection of new space debris (SD) fragments, is characterized by an asymmetry in the distribution of the average daily number of events in longitude - the number of average daily NMEs at 75∘E is higher than at longitude 255∘E. An analysis of the dependence of the average daily number of NMEs on the minimum distance between objects as a function of the catalog epoch showed that the average daily number of NMEs at the distances of up to 1 km increased from 0.22 events per day in 2011 to 0.35 events per day in 2020. If we take a distance of 20 m as a collision measure, then according to 2020, the probability of such an event in the GSO is one event in 8 years. The analysis showed that if the current dynamics of population growth at the GSO continues in the future, then by 2030 there will be a situation in which a collision may occur every 5 years, and by 2040 every 3 years. |
| 28 |
Analysis of lutetium-177 production at the WWR-K research reactor |
Sairanbayev D., Koltochnik S., Shaimerdenov A., Chakrova Y., Gurin A., Kenzhin Y. |
2021 |
APPLIED RADIATION AND ISOTOPES 169 (2021) 109561, Q2 |
Production of lutetium-177 using direct nuclear reaction 176Lu(n,γ)177Lu by WWR-K reactor neutrons on enriched LuCl3 (up to 82% of 176Lu) is described. Calculations were performed by MCNP6 transport code. Two different irradiation positions of the WWR-K research reactor were considered. Estimates of the maximum specific activity of the luthetium-177 are obtained for the reactor irradiation positions located: (a) in the reactor core centre, (b) in the core periphery. In these positions, thermal neutron flux is two times different. Experimental data was shown that k-factor is 1.5 for considered irradiation positions. The study shows that for the position located in the core center, the estimated maximum specific activity of lutetium-177 is 819 GBq/mg, is to be achieved after 15 days of irradiation. For the position located in the core periphery, specific activity of lutetium-177 is 561 GBq/mg, is to be achieved after 20 days of irradiation. Ratio of Lu-177m to Lu-177 specific activity is not more than 0.025 for both irradiation positions. |
| 29 |
Creative thinking as a driver for students' transition to university 4.0 model |
Murzagaliyeva A., Jugembayeva B. |
2021 |
Thinking Skills and Creativity, 2021, 41, 100919, Q1 |
The dynamics of the modern world and the transformation of the labor market put forward new requirements for education, aimed today at the formation of the necessary skills and the development of the ability to innovate, which becomes the basis of a new paradigm of education, embedded in the University 4.0 model. The purpose of the article is to study the readiness of students for creative and innovative activities in the context of the transition to the University 4.0 model on the example of [BLINDED] University. A study of the intellectual prerequisites of readiness for innovative activities of 236 physics students was carried out before and after training. At the beginning of the experiment, psychological testing was carried out to determine the characteristics of thinking and the creative component of a personality using valid psychodiagnostic techniques. Students completed training sessions for 1 month; the training included solving logical and situational tasks, business games, and brainstorming. The training was aimed at developing cognitive shifting, concentration of attention (a high level of intellectual lability before training was observed in 24.6% of students, after training - in 40.7% of students), inductive, logical, practical thinking (a high level of these indicators before training was found in 23.3% of students, after training - in 36.9% of students), imagination (the number of students with a high level of image changed from 28.4% to 51.7%), creative, entrepreneurial, and managerial abilities (a high level of which after the training was shown by 11.0% of students, in comparison with 6.4% before the training). The results of the study showed a statistically significant improvement in all the parameters. The results obtained allow concluding that it is necessary to revise and improve curricula and programs to bring them in line with the new paradigm of education within the framework of the University 4.0 model with the obligatory addition of moral, ethical, and spiritual components. The novelty/value of this research lies in the study of the intellectual prerequisites of students for innovative activities and the proof of the possibilities of their development in the process of studying at a university. |
| 30 |
Testing Primordial Black Holes as Dark Matter in Supergravity from Gravitational Waves |
Bogachev, A.A., Kozulin, E.M., Knyazheva, G.N., Itkis, I.M., Itkis, M.G., Novikov, K.V., Kumar, D., Banerjee, T., Diatlov, I.N., Cheralu, M., Kirakosyan, V.V., Mukhamejanov, Y.S., Pan, A.N., Pchelintsev, I.V., Tikhomirov, R.S., Vorobiev, I.V., Maiti, M., Prajapat, R., Kumar, R., Sarkar, G., Trzaska, W.H., Andreyev, A.N., Harca, I.M., Vardaci, E. |
2021 |
Physical Review C, 2021, 104(2), 024623, Q1 |
Background: Observation of asymmetric fission of Hg180 has led to intensive theoretical and experimental studies of fission of neutron-deficient nuclei in the lead region. Purpose: The study of asymmetric and symmetric fission modes of Hg180,190 and Pb184,192,202 nuclei. Methods: Mass-energy distributions of fission fragments of Hg180,190 and Pb184 formed in the Ar36+Sm144,154 and Ca40+Sm144 reactions, respectively, at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET and compared with previously measured Pb192,202 isotopes produced in the Ca48+Sm144,154 reactions. The mass distributions for Hg180,190 and Pb184,192,202 together with old data for Ir187, Au195, Hg198, Tl201, Bi205,207, Po210, and At213 [J. Nucl. Phys. 53, 1225 (1991)] have been decomposed into symmetric and asymmetric fission modes. The total kinetic-energy distributions for different fission fragment mass regions have been analyzed for Hg180,190 and Pb184. Results: The stabilization role of proton numbers at Z≈36, 38, Z≈45, 46, and Z=28/50 in asymmetric fission of excited preactinide nuclei has been observed. The high (≈145-MeV) and the low (≈128-MeV) energy components have been found in the total kinetic-energy distributions of Hg180,190 fission fragments corresponding to the fragments with proton numbers near Z≈46 and Z≈36, respectively. In the case of fission of Pb184 only the low-energy component (≈135MeV) for the fragments with masses corresponding to the proton numbers Z≈36 and 46 has been found. Conclusions: The studied properties of asymmetric fission of Hg180,190 and Pb184,192,202 nuclei point out the existence of well deformed proton shell at Z≈36 and less deformed proton shell at Z≈46. |
| 31 |
The rise of muon content in extensive air showers after the 3 PeV knee of the |
A.L. Shepetov , S.B. Shaulov, O.I. Likiy, V.A. Ryabov, T.Kh. Sadykov, N.O. Saduev, |
2021 |
Astroparticle Physics 133 (2021) 102642, Q2 |
We put together the experimental results on muon component of extensive air showers (EAS) which were gained with various techniques at the detector complex of the Tien Shan mountain station. According to this comparison, the problem of the EAS muon content in the range of primary cosmic ray energies (1–100)PeV seems to be more complicated than it was usually supposed. Generally, from the models of nuclear interaction it follows that the EAS which have produced gamma-hadron families in the Tien Shan X-ray emulsion chamber did preferably originate from interaction of the light cosmic ray nuclei, such that their muon abundance must be ∼1.5 times below an average calculated over all showers. In contrary, the experimental muon counts in the EAS with families demonstrate a (1.5–2)-fold excess above the average, and this difference starts to be observable in the showers with the energy above the 3PeV knee of the primary cosmic ray spectrum. Later on, the rise of muon production in EAS after the knee was confirmed at Tien Shan by another experiment on detection of the neutrons stemmed from interaction of cosmic ray muons. Thus, the results obtained by the two completely different methods do mutually agree with each other but contradict to the common models of hadron interaction. |
| 32 |
Search and research of K NNN ¯ and K¯ K NN ¯ antikaonic clusters |
Roman Ya. Kezerashvili, Shalva M. Tsiklauri, Nurgali Zh. Takibayev |
2021 |
Progress in Particle and Nuclear Physics |
This review presents the current status of experimental searches and theoretical studies of antikaonic four-body K̄NNN and K̄K̄NN clusters. Theoretical approaches within the framework of non-relativistic potential models used for the investigation of four-body K̄NNN and K̄K̄NN clusters, such as the variational, Faddeev equations, and hyperspherical harmonics are considered. The results of calculations for the binding energies and the widths obtained within these methods by employing diverse sets of nucleon–nucleon, effective K̄N, and antikaon–antikaon interactions are presented, discussed, and compared with the calculations using the method of hyperspherical harmonics in momentum representation. The presented results demonstrate that the quasibound state energy of antikaonic four-body K̄NNN and K̄K̄NN clusters is not sensitive to the NN interaction, and show a very strong dependence on the K̄N potential. Despite the strong short-range repulsion due to the NN interaction in K−ppp and K−K−pp and the weak K̄K̄ repulsion in K−K−pp, the antikaonic clusters K−ppp and K−K−pp are strongly bound. |
| 33 |
Experiments on tritium generation and yield from lithium ceramics during neutron irradiation |
Blynskiy P., Chikhray Y., Kulsartov T., Gabdullin M., Zaurbekova Z., Kizane G., Kenzhin Y., Tolenova A., Nesterov E., Shaimerdenov A. |
2021 |
International Journal of Hydrogen Energy, V. 46, № 13. P. 9186-9192, Q2 |
The vacuum extraction method with a mass spectrometry registration of tritium is presented in paper. It can provide a full-range analysis of gas phase composition in the chamber with samples under neutron irradiation. Lithium ceramics Li2TiO3 in the form of pebbles with lithium enrichment on 6Li isotope of 96% was examined. The paper shows the results of reactor experiments on study the extraction of tritium-containing molecules from lithium ceramics Li2TiO3 at various temperatures and reactor power levels at the WWR-K research reactor (Almaty, Kazakhstan). The time dependences of tritium yield from the ampoule with ceramics during reactor irradiation were obtained. Near-surface concentrations of tritium and hydrogen atoms on the ceramics surface under reactor irradiation were estimated. |
| 34 |
Analysis of reactor experiments to study the transfer processes of generated tritium in lithium cps (capillary-porous system) |
Askerbekov, S., Kenzhina, I., Kulsartov, T., Kadyrzhanov, K., Nesterov, E, et al. |
2021 |
International Journal of Hydrogen Energy, 2021, Q2 |
To date, there have been many studies on the possibility of using lithium CPS as a plasma-facing material in fusion reactors. For use such liquid-lithium systems in fusion reactors, it is necessary to determine the interaction parameters of the surface facing the plasma with the working gases under conditions simulating the real operation of the facility, i.e. under conditions of neutron and gamma radiation. Therefore, this paper is devoted to the study of the processes of hydrogen isotopes interaction with lithium CPS under reactor irradiation. The experiments presented in work were carried out at the IVG1.M research reactor by using dynamic sorption method with the presence of deuterium under the lithium CPS sample. The results of reactor experiments simulation, in particular, the distribution of tritium concentration in lithium volume and traps, and the flows of tritium released through the inner surface of the CPS into the experimental chamber at different temperatures are presented. Based on the simulation results, the following interaction parameters of tritium with lithium were determined: temperature dependences of tritium capture constant by lithium and the dissociation constant of LiT. The obtained model can be applied for analysis of tritium generation and release from different lithium-containing materials used as a filling of CPS structure (for example, lithium and tin-lithium eutectics). |
| 35 |
Structures of the excited states in 9 Be studied by scattering of 23 MeV deuterons |
Starastsin, V., Demyanova, A., Danilov, A., Janseitov D., Adamian, G., Antonenko, N., et al. |
2021 |
European Physical Journal A, 2021, 57(12), 334, Q2 |
An experiment on the scattering of 23 MeV deuterons by 9Be nucleus was carried out. Differential scattering cross sections are obtained for the following states: g.s., 1.68 MeV, 2.43 MeV, 2.78 MeV, 3.05 MeV, 3.82 MeV, 4.70 MeV, 5.59 MeV, 6.38 MeV, 6.76 MeV and 7.94 MeV. The obtained data were analyzed using the distorted wave Born approximation (DWBA) and modified diffraction model (MDM). It was confirmed that the positive parity band Kπ = 12+ based on the 1.68 MeV, 12+ state is formed by the 3.05 MeV, 52+; 4.70 MeV, 32+ and 6.76 MeV, 92+ states. It was proposed that the 3rd band (Kπ = 12-) based on the 2.78 MeV, 12- state may be formed by the 5.59 MeV, 32- and 7.94 MeV, 52- states. The radii of these band states (Kπ = 12+ and Kπ = 12-) are increased compared to the ground state. Besides, it is found that the 3.82 MeV state has Jπ = 32- and does not belong to any of the rotational bands considered above. Possibly, it is formed as a one-particle state near the excited 8Be core with the spin Jc = 2. |
| 36 |
Asymmetric and symmetric fission of excited nuclei of Hg 180,190 and Pb 184,192,202 formed in the reactions with Ar 36 and Ca 40,48 ions |
Bogachev, A.A., Kozulin, E.M., Knyazheva, G.N., Harca, I.M., Vardaci, E., Mukhamejanov Y.S., et al. |
2021 |
Physical Review C, 2021, 104(2), 024623, Q2 |
Background: Observation of asymmetric fission of Hg180 has led to intensive theoretical and experimental studies of fission of neutron-deficient nuclei in the lead region. Purpose: The study of asymmetric and symmetric fission modes of Hg180,190 and Pb184,192,202 nuclei. Methods: Mass-energy distributions of fission fragments of Hg180,190 and Pb184 formed in the Ar36+Sm144,154 and Ca40+Sm144 reactions, respectively, at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET and compared with previously measured Pb192,202 isotopes produced in the Ca48+Sm144,154 reactions. The mass distributions for Hg180,190 and Pb184,192,202 together with old data for Ir187, Au195, Hg198, Tl201, Bi205,207, Po210, and At213 [J. Nucl. Phys. 53, 1225 (1991)] have been decomposed into symmetric and asymmetric fission modes. The total kinetic-energy distributions for different fission fragment mass regions have been analyzed for Hg180,190 and Pb184. Results: The stabilization role of proton numbers at Z≈36, 38, Z≈45, 46, and Z=28/50 in asymmetric fission of excited preactinide nuclei has been observed. The high (≈145-MeV) and the low (≈128-MeV) energy components have been found in the total kinetic-energy distributions of Hg180,190 fission fragments corresponding to the fragments with proton numbers near Z≈46 and Z≈36, respectively. In the case of fission of Pb184 only the low-energy component (≈135MeV) for the fragments with masses corresponding to the proton numbers Z≈36 and 46 has been found. Conclusions: The studied properties of asymmetric fission of Hg180,190 and Pb184,192,202 nuclei point out the existence of well deformed proton shell at Z≈36 and less deformed proton shell at Z≈46. |
| 37 |
The prolonged gamma ray enhancement and the short radiation burst events observed in thunderstorms at Tien Shan |
A. Shepetov V. Antonova O. Kalikulov O. Kryakunova A. Karashtin V. Lutsenko S. Mamina K. Mukashev V. Piscal M. Ptitsyn V. Ryabov T. Sadykov N. Saduev N. Salikhov Yu. Shlyugaev L. Vildanova V. Zhukov A. Gurevich |
2021 |
Atmospheric Research, 2021, 248, 105266, Q1 |
We report the observation results of the hard radiation flashes which accompanied the lightning discharges above the mountains of Northern Tien Shan. Time series of the counting rate intensity, numerical estimations of absolute flux, and energy distribution of accelerated electrons and of (20−2000) keV gamma rays were obtained at the height of 3700 m a. s. l., immediately within thunderclouds, and in closest vicinity (≲100 m) to discharge region. Two different kinds of radiation emission events are presented here: a relatively prolonged rise of gamma ray intensity with minute-scale duration (the thunderstorm ground enhancement, TGE) which has preceded a negative field variation, and a short sub-millisecond radiation burst, which accompanied a close lightning discharge in thundercloud. It was revealed also an indication to positron generation in thunderclouds at the time of gamma ray emission, as well as modulation of the neutron counting rate in Tien Shan neutron monitor which was operating at a (1.5–2) km order distance from the region of lightning development. |