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Vol 89, No 8 (2025)
Fundamental problems and applications of physics of atomic nucleus
Emission of high-energy 4He and 6.7Li nuclei in nuclear reaction of 56Fe ions on 238U target
Abstract
Energy spectra of alpha particles and 6.7Li nuclei emitted at an angle of 0° in the reaction of a 56Fe beam (400 MeV) on a 238U target were measured using a high-resolution magnetic analyzer (MAVR setup). The emission of these particles was observed in a wide energy range, up to 120–130 MeV. Several mechanisms for the formation of these nuclei associated with the processes of multinucleon transfer and incomplete fusion were proposed based on an analysis of the kinematic limits of the exit channels and the application of the moving source model.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1180-1187
1180-1187
Preparation and conducting experiments on the irradiation of biological models in a proton beam
Abstract
The preparation and conducting experiments on proton irradiation in flash therapy modes at the accelerator of INR RAS of biological models on the example of fertilized eggs of Japanese quail (Coturnix japonica) were performed. The study includes evaluation of the results of computer simulation of the INR RAS facility using Geant4 simulation tools.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1188-1193
1188-1193
Study of flash effects at the proton accelerator of INR RAS
Abstract
A brief overview of the results and methods for conducting radiobiological experiments to study the patterns of flash effect at the linear proton accelerator of INR RAS is presented. An increase in apoptosis of tumor cells compared to normal cells was found when the dose rate increased to extreme values.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1194-1200
1194-1200
Target dependence of the isotope distributions in heavy-ion reactions at Fermi energies
Abstract
Heavy-ion reactions with energies close to Fermi energy are of interest because they exhibit the features of the deep inelastic transfer and direct reactions. The transport-statistical approach describes sufficiently well the cross-sections of isotopes not far from the stability line and allows them to explain their dependence on the mass of the target. In this paper the comparison of transport-statistical calculations with other available models is also presented.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1201-1207
1201-1207
Study of the charged particles correlations in Xe+W interactions at an energy of 3.0 GeV/nucleon
Abstract
Experimental results on spatial correlations of charged particles in 124Xe+W interactions at the energy of 3 GeV/nucleon obtained at the Nuclotron internal target station are presented. The simulation of the experimental setup detectors has been performed using the Geant4 software package and the PHQMD event generator.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1209-1215
1209-1215
Magnetized nuclei in r-process
Abstract
The synthesis of ultramagnetized heavy atomic nuclei during type II supernova explosions and neutron star mergers is considered. For a magnetic field of 0.1–10 ТТ the Zeeman effect leads to a linear nuclear magnetic response, which can be described in terms of magnetic susceptibility. Under the influence of magnetic fields, the path of the r-process changes with an increase in the proportion of nuclei with masses less than magic, as well as an enhancement of the volume of nuclides of smaller masses at the r-process peaks.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1216-1221
1216-1221
Microscopic analysis of elastic scattering and transfer reactions in the 7Li+10B collision at a beam energy of 58 MeV
Abstract
The results of theoretical analysis of experimental data on the cross-sections of elastic scattering of 7Li+10B and the neutron transfer reaction in collisions of these nuclei, which were obtained at the beam energy of ELAB=58 MeV at the U-400 cyclotron in the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research, are presented. The calculations of the cross-sections were carried out based on a microscopic model of optical potential and the method of distorted waves.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1222-1226
1222-1226
Towards accounting of the diffraction dissociation of nucleons in nucleus-nucleus interactions
Abstract
The FRITIOF model, widely used in Monte Carlo generators of artificial events, in particular, in the Geant4 software package, is supplemented by the treatment of the formation and interactions of diffraction-produced systems in nuclei. A good description of the first experimental data of the NICA BM@N collaboration on the production of π+ mesons in interactions of 40Ar nuclei with various nuclei at the energy of 3.2 · A GeV is obtained.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1227-1231
1227-1231
Cross sections of photoneutron reactions for light and medium-heavy nuclei in experiments on bremsstrahlung beams
Abstract
The photoneutron partial reaction cross sections (γ, 1n) and (γ, 2n) on 52Cr and 90Zr obtained using corrections calculated on the base of statistical theory to the neutron yield cross sections σ(γ, xn) = σ(γ, 1n) + 2σ(γ, 2n) determined in experiments carried out on the beams of bremsstrahlung were analyzed using objective physical criteria of data reliability. The reasons that experimental data for 90Zr satisfy physical criteria but there are serious doubts in reliability of data for 52Cr, are discussed.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1232-1240
1232-1240
Studies of angular distributions and cross sections of gamma-ray radiation on Si and O nuclei in reactions with fast neutrons
Abstract
Within the framework of the TANGRA project, the experimental installation was created to measure the angular distributions and cross sections of gamma-ray radiation in reactions (n, Xγ) during the interaction of neutrons with an energy of 14.1 MeV with Si and O nuclei. We described the design features of the installation and the method of processing the experimental data obtained.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1241-1248
1241-1248
Search for single and tri-nucleon decays of 76Ge in GERDA
Abstract
The possibility of single- and tri-nucleon decays that violate baryon number conservation is predicted in several extensions of the Standard Model. The main goal of the GERDA experiment was to search for neutrinoless double beta decay of 76Ge. In addition, other important results of GERDA were obtained in searching for various processes beyond the Standard Model. They include the search for a possible manifestation of inclusive, mode-independent decays of single neutrons and protons, as well as certain modes of tri-nucleon decay in 76Ge nucleus. The results of such investigations are presented.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1251-1256
1251-1256
Formation of correlated charged particles at absorption of π−-meson in a live target
Abstract
The results of the analysis of energy spectra correlated at an angle of 180° pairs of single-charged particles by the nuclei of a live target (an analogue of the 28Si target) at the absorption of stopped π−-mesons are presented. The information obtained with the help of a live target is interesting from the point of view of testing hypotheses about the mechanisms of formation of complex particles. Data analysis made it possible to detect complex particles, both of cluster direct origin and formed because of secondary intracellular interactions.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1258-1261
1258-1261
Study of the structure of 12C and 6Li nuclei in the α-cluster and shell models
Abstract
Wave functions of the ground state of the 12C and 6Li nuclei in the α-cluster model are calculated using Feynman’s path integrals and hyperspherical functions. The energy of separation to α-particles and the charge distributions were calculated and agreement with experimental data was obtained. In addition, the shell model of the deformed nuclei is used to calculate the nucleon states in the 12C nucleus for comparison against α-cluster model.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1262-1272
1262-1272
Towards understanding of Ks 0-meson production in proton-proton interactions
Abstract
Mechanisms of Ks
0-meson production can be studied using two-particle transverse-momentum (PT) correlations. The correlations between Ks
0-mesons and hadrons produced in proton-proton interactions at center-of-mass energy of NN collisions of 10 GeV are considered in the Geant4/FTF and Pythia 6.4 models. The strong PT-correlations between Ks
0-mesons and Λ-hyperons, K+-mesons, and protons are observed. The study of the two-particle correlations is important to clarify the particle fragmentation functions and can be implemented at NICA SPD experiment.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1273-1279
1273-1279
New results on the pp-scattering simulation for the beam—beam counter at NICA SPD
Abstract
The results on the pp-scattering simulation at the total energy up to 27 GeV for the Beam—Beam Counter at SPD are presented. The simulation has been performed using the Pythia8 generator under SPDRoot framework. The estimations of the magnetic field influence on the inclusively charged particles production asymmetries and on the Beam—Beam Counter loads have been obtained.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1280-1285
1280-1285
Electron-positron pair spectrometer calculation in setup for studying reaction between fast neutron and light nucleus
Abstract
Electron and positron motion were simulated in spectrometer based on constant magnetic dipole and their detection in position-sensitive silicon detectors. Resolution on emitted electron and positron energy and angle was obtained. Spectrometer is a part of setup for studying rare intranuclear processes in light nuclei with the production of internal conversion pairs.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1285-1290
1285-1290
Model of nucleon clustering and fragment formation in heavy nuclei fission
Abstract
We considered the problem of theoretical description of the fission fragment formation within the framework of an extended Vicsek-type collective model. The non-mean-field approach is based on microscopic modeling of the nucleon clustering as a phenomenon of particle aggregation due to short-range mutual interaction. Numerical computer simulations were carried out for the 208Pb cluster, observed experimentally in the multimodal fission of heavy and superheavy nuclei.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1291-1295
1291-1295
Study of the identified charged hadron production processes in the PHENIX experiment
Abstract
The paper presents recent PHENIX measurements of identified charged hadron production (π+, K+, p, β) in p+Al, 3He+Au, Cu+Au at √sNN = 200 GeV and in U+U at √sNN = 193 GeV. The measured values of p/π+ and β/π− are compared with the predictions of the AMPT (string melting version) and PYTHIA/ANGANTYR program packages. The integral values of p/π+, β/π−, K+/π+, K−/π− as a function of the number of participating nucleons are presented.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1297-1301
1297-1301
On fragments emission in collisions of intermediate-energy heavy ions based on a non-equilibrium hydrodynamic approach
Abstract
In the nonequilibrium hydrodynamic approach, a description of the experimental data of ITEP on double differential cross sections of the emission of 11Be and 12B nuclei at an angle of 3.5° in the reaction 12C+9Be→ → f+X at an energy of 300 MeV per nucleon for incident carbon nuclei is obtained. A comparison with other models is made and the dynamics of the fragmentation process is analyzed.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1302-1306
1302-1306
Study of nanocarbon spontaneous emission centers on the cathodes of multiwire proportional chamber of the LHCb muon detector
Abstract
It has been established that because of long-term operations in experiments at the LHC, nanocarbon structures form on the cathodes of multiwire proportional chambers of the LHCb muon detector. The appearance of such structures is the cause of spontaneous self-sustained currents in the chambers. The current emission centers are growing due to the absorption of the gas mixture dissociation products on the copper cathode. The process occurs under normal conditions, which is unusual for nanostructures, and is not reproducible in laboratory aging tests.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1307-1318
1307-1318
Neutron-induced fission cross section of 237Np up to 500 MeV
Abstract
The simultaneous measurements of the angular distributions of fragments and the fission cross section of 237Np by neutrons in the energy range from 0.3 MeV to 500 MeV were carried out on the neutron time-of-flight spectrometer GNEIS at the Petersburg Nuclear Physics Institute of NRC "Kurchatov Institute". We presented a brief description of the experimental setup and compares the data obtained with the results of experiments performed earlier.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1319-1325
1319-1325
Detector optimization based on artificial neural network training
Abstract
We apply artificial neural networks for event-wise analysis of model data for a microchannel plate detector. Based on this data, we estimate an impact parameter, and the collision point coordinates for each event. We have performed the analysis based on several Monte-Carlo collision models. Even though the quality of the existing models is not sufficient for a reliable, model-independent estimation of the collision parameters, the proposed method of parameter reconstruction allows us to estimate the optimal technical characteristics of the detector.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1326-1333
1326-1333
On the applicability of the EPOS4 and UrQMD (LHC) generators for the analysis of 7 TeV pp-collisions
Abstract
We compared the results of the EPOS4 and UrQMD 3.4 (LHC) event generators using the example of pp-collisions at ultra-high energies (7 TeV). Violation of the laws of conservation of baryon and lepton charges and conservation of energy in EPOS4 is shown. A comparison with experimental data is made, the influence of event filtering by conservation of energy and baryon and lepton charges on the multiplicity distribution in the pseudorapidity range |η| ≤ 1.5 is studied.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1334-1337
1334-1337
Obtaining evaluated values of nuclear-physical decay characteristics for nuclei with superallowed beta transitions
Abstract
A new evaluation of half-live values and branching ratios for 10 superallowed 0+ → 0+ beta decays is presented. The values of ft, including those corrected for theoretical adjustments, are obtained. The evaluation is carried out using an improved reliability criterion for the assessed values. A new estimate of Ft values and a comparison with other authors' evaluations are provided.
Bulletin of the Russian Academy of Sciences: Physics. 2025;89(8):1339-1344
1339-1344