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Vol 87, No 3 (2024)
ЯДРА. Теория
PROPERTIES OF OCTUPOLE STATES 238U
Abstract
The energies and electrical properties of the octupole states of the 238U nucleus are studied within theframework of a phenomenological model considering the Coriolis mixing of rotational bands. Mixing ofthe low-lying negative parity bands is considered. The energies, the structures of states of rotational bandswith Kπ=0−,1−,2−,3− and the reduced probabilities of Е1 transitions are calculated. Theoretical energyvalues and Е1-transitions’ probabilities are compared with the experimental data. Good agreement betweenexperimental data and theoretical results is obtained.
Âdernaâ fizika. 2024;87(3):128-138
128-138
ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ. Эксперимент
CHARACTERISTICS OF THE EAS NEUTRON COMPONENT WITHACCOUNTING FOR THE EFFICIENCY OF NEUTRON DETECTION
Abstract
A new algorithm for selecting signals caused by the detection of neutrons is described. The estimates of itseffectiveness for the PRISMA-32 and URAN arrays are presented. Using this algorithm, for various air-shower sizes the number of neutrons was reconstructed, the time distributions of neutrons and their lateraldistribution functions were obtained.
Âdernaâ fizika. 2024;87(3):139-146
139-146
PROJECT OLVE (OBSERVATORY OF HIGH-ENERGY COSMICRAYS): OBJECTIVES AND DESIGN FORM
Abstract
The High Energy Cosmic Ray Observatory (HERO) is an experimental design for the direct study of cosmicrays based on the use of an ultra-heavy ionization calorimeter. The effective geometric factor of the facilitywill be at least 12 2sr for cosmic-ray protons and at least 16–20 2sr for nuclei and electrons. During 5–7 years of exposure, this mission will make it possible to measure the energy spectra of all common andrare cosmic-ray nuclei in the energy region 1012–1016 eV/particle with element-by-element resolution ofthe charge of nuclei and with sufficiently high energy resolution. It is planned to study not only the chargerange of cosmic-ray nuclei Z=1−26, but also the detection of super-heavy nuclei beyond the iron peak,as well as high-energy electrons, positrons and gamma rays. The main objectives, design appearance andcharacteristics of the space mission are discussed.
Âdernaâ fizika. 2024;87(3):147-155
147-155
THE POSSIBILITY OF DETECTING TeV ELECTRONS ANDPOSITRONS OF GALACTIC COSMIC RAYS USING THE EARTH’SMAGNETIC FIELD
Abstract
The research of the electron and positron spectrum of galactic cosmic rays is an important task of high-energy astrophysics. The necessity of using new methods of electron and positron registration is caused byinsufficient statistical reliability of data from modern experiments in the TeV energy range. In the presentwork, one of the possible registration methods based on the use of synchrotron radiation of electronsand positrons in the Earth’s magnetic field is investigated. Using modeling of trajectories of high-energyelectrons, positrons, and synchrotron photons emitted by them, the detector count rate for the ISS and ROS orbit has been estimated. The possibility of separation of electrons and positrons using this method isshown.
Âdernaâ fizika. 2024;87(3):156-161
156-161
SEARCH FOR HIGH-ENERGY GAMMA QUANTA FROMTHE CYGNUS COCOON SOURCE IN OCTOBER–NOVEMBER 2020
Abstract
In November 2020, the IceCube neutrino Observatory registered a neutrino event with an energy of 150 TeV directed at the Cygnus Cocoon gamma-ray source. In the Carpet-2 experiment, as part of the Baksan Neutrino Observatory (BNO), a sharp increase in the flow of events with an energy of more than 300 TeV was recorded from the same direction within the angular accuracy of the events. This flux is 4 orders of magnitude higher than the expected intensity of gamma quanta of this energy region according to data in the region of less than 100 TeV. It was expected that such a powerful flare could be registered by the TAIGAHiSCORE installation of the TAIGA astrophysical complex. We analyzed the events of the EAS recorded by the installation of TAIGA-HiSCORE for 18 hours in October-November 2020 fromthe Cygnus Cocoon source. The article provides the upper limit of the expected excess flow.
Âdernaâ fizika. 2024;87(3):162-169
162-169
BOSE–EINSTEIN CONDENSATION AND MUON PRODUCTION IN ULTRA-HIGH ENERGY COSMIC RAY PARTICLE COLLISIONS
Abstract
Collisions of cosmic ray particles with ultra-high initial energies with nuclei in the atmosphere open a wide room for appearing of the novel dynamical features for multiparticle production processes. In particular, the laser-like behavior of pions driven by Bose–Einstein condensation would result in the shift to larger multiplicities and, as consequence, could provide, in general, the enhanced yield of cosmic muons. In the present work the critical value of the space charged particle density for onset of Bose–Einstein condensation of the boson (pion) wave-packets into the same wave-packet state is estimated within the model with complete multiparticle symmetrization for the energy domain corresponding to the ultra-high energy cosmic rays (UHECR). Energy dependence of mean density of charged pions is evaluated for the cases of absence of the Bose–Einstein effects and for presence of laser-like behavior of pions. The possible influence of the Bose–Einstein condensation is discussed for the muon production inUHECRparticle collisions with the atmosphere.
Âdernaâ fizika. 2024;87(3):170-181
170-181
KINEMATIC DESCRIPTION OF ALIGNMENT EFFECT IN COSMIC RAYS
Abstract
The important role of kinematic constraints for the origin of the alignment of hadron and photon families observed by the Pamir collaboration in emulsion experiments with cosmic rays is discussed. Within the framework of the suggested approach it is shown that the high degree of alignment of the interaction products of the target nuclei and cosmic rays can be a consequence of the selection procedure of the most energetic clusters of particles together with the law of conservation of transverse momentum. The obtained results correctly describe the experimental data for three energetic centers and are also close enough to the measurements in the case of four and five clusters, which indicates encouraging prospects for the proposed method of explaining the alignment phenomenon.
Âdernaâ fizika. 2024;87(3):182-190
182-190
K0𝑆-MESON PRODUCTION IN 兀− −𝐴-INTERACTIONS AT ACCELERATOR COMPLEX U-70
Abstract
First results on 𝐴-dependence measurements in inclusive K0𝑆-meson production in 兀− 𝐴-interactions (𝐴 = C, Cu, Al, Sn, W) are presented at 26.5 GeV/c. The ratios of the differential cross sections of four of these nuclei to the differential cross section on aluminum were measured and the dependence of these cross-sections on the atomic number of the nucleus was studied. The measurements were carried out in the kinematic region of the Feynman variable 0.2 < 𝐹 < 0.8 and transverse momentum 𝑝𝑇 < 1.2 GeV/c. K0𝑆-mesons were detected in the decay mode K0𝑆→ 兀+兀−-at the SPASCHARM experimental setup using negative charged beams at beamline 14 of the U-70 accelerator complex.
Âdernaâ fizika. 2024;87(3):191-198
191-198
PROJECT ON RESEARCH OF NUCLEAR dd-SYNTHESIS WITH POLARIZATION OF INITIAL PARTICLES AT LOW ENERGIES (PolFusion)
Abstract
The nuclear dd-fusion reaction can proceed by three possible channels: 3H + 𝑝 (≈ 50%), 3He + 𝑛 (≈ 50%), 4He + (≈ 10−7%). Interest in dd-fusion has been aroused by both fundamental research and astrophysics and applied science, particularly in the field of fusion reactor development. In the 1970s at the Kurchatov Institute, the idea of studying the nuclear dd-fusion reaction using polarized deuteron beams was proposed. The development of this idea was continued in the PolFusion (Polarized Fusion) nuclear physics experiment, which aims to study the reaction of nuclear dd-synthesis with polarized source particles in the low energy region. The experiment is planned to measure the scattering asymmetries of dd-fusion reaction products in the final state at different mutual orientation of the spins of colliding deuterons in the energy range 10—100 keV. The authors will present an overview of the status of the experiment.
Âdernaâ fizika. 2024;87(3):199-204
199-204
ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ. Теория
ON THE IMPORTANCE OF CONSIDERATION OF INITIALLY-EXTENDED RELATIVISTIC STRINGS FOR HADRONIZATION MODELING
Abstract
Data from a number of experiments in high-energy physics indicate difficulties in the description of the production of pions and ρ0-mesons using existing models of hadronic interactions. One of the possibilities for introducing new non-collective effects is to modernize the fragmentation models of relativistic Nambu–Goto strings. As an option, the use of initially extended strings is proposed, which makes it possible to calculate string parameters in configurations that are realistic for hadronic and nucleus-nucleus interactions. For this purpose, a special gauge is introduced, suitable for calculations with arbitrary initial conditions. The ability to determine the spin–orbital characteristics of strings allows us to impose additional restrictions on the mass of string fragments.
Âdernaâ fizika. 2024;87(3):205-211
205-211
SPECTRA OF 𝑍-BOSONS AND LEPTON ANGULAR COEFFICIENTS IN THE LEADING ORDER PRA WITH THE NEXT TO LEADING ORDER CORRECTION
Abstract
The article studies the production of 𝑍-bosons in proton-proton collisions at LHC collider energies. Production cross sections and transverse momentum spectra of 𝑍-bosons have been calculated, as well as lepton angular coefficients as functions of the transverse momentum of the 𝑍-boson. Calculations were performed using the parton Reggeization approach (PRA) within the framework of the leading approximation in the strong coupling constant (𝑄¯ 𝑄 → 𝑍), taking into account the next to leading order correction from processes of quark-gluon scattering (𝑅𝑄 → 𝑍𝑞). Numerical modeling was performed using Monte-Carlo generator KaTie. The calculation results are compared with experimental data from the ATLAS collaboration.
Âdernaâ fizika. 2024;87(3):212-217
212-217
THE TEST OF THE CLASSICALITY CONCEPT IN THE ENTANGLED STATES OF NEUTRAL PSEUDOSCALAR MESONS USING THREE TIME WIGNER INEQUALITIES
Abstract
In this work we have formulated the Classicality concept. Using this concept theWigner inequalities which are dependent on three moments of time are obtained. The possibility of experimental tests of violations of these inequalities on the pure and mixed flavor states of 𝐾0-, 𝐷0- and 𝐵𝑠-meson pairs is investigated. In the framework of the Werner background model, it is shown that the violation of Wigner time-dependent inequalities can be observed even with 50% fraction of background processes.
Âdernaâ fizika. 2024;87(3):218-234
218-234
THE DESCRIPTION OF THE FOUR-PARTICLE DECAYS ¯𝐵𝑑, 𝑠 → 𝐵𝑑, 𝑠 → μ+μ−𝑒+𝑒− IN THE FRAMEWORK OF THE STANDARD MODEL
Abstract
In the framework of the Standard Model, partial widths, double and single differential distributions for four-lepton decays 𝐵𝑞 → μ+μ−𝑒+𝑒− were calculated, 𝑞 = {𝑑, 𝑠}. The contributions of the emission of a virtual photon by light 𝑞- and heavy 𝑏-quarks, the bremsstrahlung by charged leptons in the final state, the leading contribution of ”weak annihilation”, and the contribution of wide vector 𝑐𝑐-resonances are taken into account. Contributions from narrow 𝐽/ψ – and ψ (2𝑆)–resonances are excluded. The emission of a virtual photon by a light quark 𝐵𝑞–meson is described using the vector meson dominance model. Only the contribution of the lightest vector mesons, which include a 𝑞𝑞-pair, is taken into account. For the 𝐵𝑠-meson this is '(1020)–resonance. For the 𝐵𝑑–meson, the contributions of ρ0(770)– and ω(782)–resonances are taken into account. Two possibilities are considered. The first: the contributions of narrow '(1020)– and ω(782)–mesons are excluded from the partial widths of the corresponding decays. The second: the contributions of narrow resonances are taken into account. The question of the influence of the subtractive procedure on the magnitude of the partial widths of 𝐵𝑞 → μ+μ−𝑒+𝑒− decays has been studied.
Âdernaâ fizika. 2024;87(3):235-254
235-254
POSITRON SUPERCRITICAL RESONANCES AND SPONTANEOUS POSITRON CREATION IN SLOW COLLISIONS OF HEAVY NUCLEI
Abstract
We present a theoretical and computational study of positron supercritical resonances in systems consisting of two highly-charged bare nuclei. The resonance positions and widths depending on the internuclear separation are calculated with the help of the complex-scaling generalized pseudospectral method in modified prolate spheroidal coordinates. The results are applied to estimate the probability of spontaneous positron creation in slow U92+–U92+ and Cm96+– Cm96+ collisions.
Âdernaâ fizika. 2024;87(3):255-262
255-262
RADIAL AND TANGENTIAL FRICTION COEFFICIENTS: DERIVATION OF FORMULAS, CALCULATION AND APPLICATION IN MODELLING OF THE HEAVY ION COLLISION PROCESS
Abstract
A method for calculating the forces and moments of friction forces arising between two colliding nuclei with a non-zero impact parameter is considered. At this stage of the work, it was assumed that colliding nuclei remain spherical throughout the entire collision process. A simulation of the collision process of spherical atomic nuclei is carried out, taking into account their gradual inclusion in rotation around their own axes. It is shown that from the moment of the transition of the system through the Coulomb barrier to the stop of the relative rotation of colliding nuclei, it takes time about 10–21 s. It is proposed to consider the stopping of radial motion and relative rotation of colliding nuclei as conditions for capturing the projectile nucleus by the target nucleus. I.e., at the moment of capture, the system should behave like a rigid rotating dumbbell. Comparison of the results of the calculation of the capture cross sections with experimental data shows a good predictive power of the considered approximate model in the case of a strongly asymmetric reaction of 16O+ 208Pb (for all reaction energies) and in the case of high-energy reactions of 36S + 208Pb and 40Ca + 208Pb.
Âdernaâ fizika. 2024;87(3):263-273
263-273
МАТЕРИАЛЫ 73-Й МЕЖДУНАРОДНОЙ КОНФЕРЕНЦИИ ПО ЯДЕРНОЙ ФИЗИКЕ. Ядра. Эксперимент
DETERMINATION OF THE ACTIVITY OF LONG-LIVED 41Ca IN REACTOR BIOLOGICAL SHIELDING MATERIALS BY PHOTOACTIVATION METHOD
Abstract
The paper discusses a photoactivation method for determining the activity of the long-lived isotope 41Ca relative to the activity of 60Co in irradiated reactor biological shielding concrete. It is proposed to use photonuclear reactions on cobalt and calcium isotopes: 59Co(γ, 𝑛)58Co, 44Ca(γ, 𝑝)43K or 48Ca( γ, n)47Ca→47Sc. to determine the activity of 41Ca. The sensitivity of the proposed method is of the order of ∼10-6 Bq/g, provided that semiconductor spectrometers with an ultrapure germanium detector are used. The structure and chemical composition of the sample do not affect the proposed method. It avoids the long sample preparation times associated with radiochemical methods.
Âdernaâ fizika. 2024;87(3):274-281
274-281
NUCLEAR REACTIONS AT 160 MeV PROTON ENERGY ON NATURAL CALCIUM
Abstract
The study of radionuclide excitation functions in proton-induced nuclear reactions is of fundamental interest for in vivo treatment verification methods in proton therapy. However, experimental data for these reactions are very limited, especially for proton energies above 20 MeV, and show significant discrepancies. In the present work, experimental cross sections of reactions for accelerated protons with an energy of 160MeVon targets of metallic calcium of natural isotopic composition are measured. For the first time, new data have been obtained on the yield cross sections of reactions with the departure of one to five protons at 44Ca nuclei. Calculations of the obtained cross sections in the Fermi gas and Gogni–Hartree–Fock–Bogolyubov models using the TALYS1.96 program code are carried out. It is shown that pre-equilibrium processes dominate in the cross sections. It is noted that the calculated cross sections, as a rule, do not exceed 30% of the experimental ones.
Âdernaâ fizika. 2024;87(3):282-287
282-287
МАТЕРИАЛЫ 73-Й МЕЖДУНАРОДНОЙ КОНФЕРЕНЦИИ ПО ЯДЕРНОЙ ФИЗИКЕ. Ядра. Теория
SPIN DISTRIBUTION OF DOUBLE NUCLEAR FISSION WITH ACCOUNT FOR BENDING- AND WRIGGLING- MODES
Abstract
A theoretical description of the nature of the spin distribution (CP) of fragments of low-energy induced and spontaneous double fission of nuclei is carried out. For two deformed fission prefragments, a mechanism for pumping large values of their relative orbital momenta L and spins J, due to the combined influence of bending and wriggling vibrations, has been established, and analytical formulas for describing CP within the framework of such a mechanism have been obtained for the first time. It is emphasized that for this mechanism, the nucleus remains “cold” in the fission process, while in the statistical model it heats up to temperatures 1 MeV. A comparison of the calculated CP for forced double fission of actinide nuclei and with the available experimental data showed reasonable agreement both in terms of the magnitude of the average spin values and in the sawtooth shape of the dependence of CP on the atomic number of fragments, which confirms the reliability of the pumping mechanism of large spin values of deformed fission fragments. For spontaneous double fission of the nucleus , possible reasons for the discrepancy between the theoretical CP and the experiment are indicated.
Âdernaâ fizika. 2024;87(3):288-294
288-294
THE ALIGNMENT OF THE 16О(3–) NUCLEUS FORMED IN REACTIONS WITH ALPHA PARTICLES
Abstract
The angular dependence of the alignment of the 16О(3–, 6.13 MeV) nucleus formed in the reactions 16О(α, α) 16О(3–) and 15N(α, 𝑡)16О(3–) at α-particle energies of 30.3 MeV was calculated taking into account the reactions’ mechanisms that determine the cross section for the formation of the 16О(3–) nucleus and is compared with the experimental values of the alignments reconstructed from the measured functions of angular 𝑦γ-correlations. It has been established that the formation mechanisms of the 16О(3–) nucleus significantly affect its orientation characteristics. The maximum amplitude alignment of the 16О(3–) nucleus in both reactions is observed in the region of final particle emission angles in which direct mechanisms make the main contribution. At these angles, the calculated alignments are in satisfactory agreement with the experimental ones.
Âdernaâ fizika. 2024;87(3):295-299
295-299
THE VALUE AND THE SIGN ESTIMATION OF THE ROT EFFECT FOR 239,241Pu ISOTOPES DURING THEIR FISSION BY POLARIZED NEUTRONS IN THE RESONANT ENERGY REGION
Abstract
It is proposed to measure the shift in the angular distribution of light charged particles (LCP) in ternary fission caused by polarized neutrons of plutonium isotopes in the resonance region with 𝐸𝑛 = 0.264 eV for the 241Pu target and 𝐸𝑛 = 0.294 eV for the 239Pu target. The reliability of interpretation of these experiments will compare favorably with measurements carried out previously at 𝐸𝑛 = 4.5 meV. The advantage is associated with a noticeable weakening of the influence of resonances, the parameters of which may raise some doubts. We are talking about resonances introduced at neutron energies 𝐸𝑛 < 0 eV. In addition, in the region of these two resonances, the fractions of impurity partial cross sections with a spin different from the spin of the resonance itself are small. It is important that the magnitude of the effects expected at the indicated resonance energies will be significantly greater than those previously obtained in the cold neutron energy region.
Âdernaâ fizika. 2024;87(3):300-307
300-307
ACCOUNT OF NON-NUCLEONIC DEGREES OF FREEDOM IN NUCLEAR MATTER
Abstract
A two-component formalism has been developed for the reaction matrix in a nuclear medium in the case of nucleon–nucleon interaction taking into account additional non-nucleonic degrees of freedom. The approach is based on the dibaryon model of nucleon-nucleon interaction, which recently allowed to describe partial 𝑁𝑁 scattering amplitudes for the channels with total angular momentum 𝐽 ≤ 3 in a wide energy range fromzero to 0.6–1 GeV, and also to reproduce successfully the positions of the known dibaryon resonances for a number of channels. The bound states in the nuclear medium that arise for such a model are studied. An equation of state for symmetric nuclear matter has been calculated within the framework of the Brueckner–Hartree–Fock scheme.
Âdernaâ fizika. 2024;87(3):308-318
308-318