abstract

In this paper, we investigate the role of potential deformation in explaining the \(\alpha \)-decay. The deformation of the nuclear potential has been taken into account by adding a Gaussian potential to the well-known Wood–Saxon potential. For the numerical calculations, the Wentzel–Kramers–Brillouin method has been used, and also the Bohr–Sommerfeld quantization condition has been employed to restrict the parameters. The half-lives of ten nuclei have been calculated for \(\alpha \)-decay and very good agreement has been obtained with the experimental data.

abstract

Computer simulations of the transition of quarks to hadrons, hadrons to quark–gluon plasma, and plasma to hadrons have been carried out. Nonlinear quark–gluon dynamics is considered a quantum process within the framework of discrete mappings. The dynamic variable is the momentum fraction \((x)\) of the QCD parton, which acts as a one-dimensional Poincaré section in the momentum phase space. The probability of finding a certain fraction of the momentum of a parton at a given moment is determined by the momentum distribution of the partons at the previous moment in time. At critical values of the control parameter, bifurcations of phase quark–gluon trajectories occur. As a result of the counteraction of the processes of emission and absorption of gluons, stable attractor quark–gluon structures are formed. The Poisson stability is determined by the Lyapunov exponents. The sequence of bifurcations converges and chaos arises. The change from regular quark–gluon dynamics to irregular chaotic one corresponds to the limit of multiple hadronic processes and the emergence of quark–gluon matter in the deconfinement state. Chaotization of the dynamical system leads to thermalization of the quark–gluon medium.

abstract

Astrophysical \(S\)-factors at zero energy for the direct nuclear capture reactions \(^{3}{\mathrm {He}}(\alpha , \gamma )^{7}{\mathrm {Be}}\), \(^{3}{\mathrm {H}}(\alpha , \gamma )^{7}{\mathrm {Li}}\), and \(^{7}{\mathrm {Be}}(p, \gamma )^{8}{\mathrm {B}}\) are estimated within the framework of a two-body potential cluster model on the basis of extranuclear capture approximation of Baye and Brainis. The values of \(S(0)\)-factors have been calculated using two different potential models for each process, which were adjusted to the binding energies and empirical values of the asymptotical normalization coefficients from the literature. New values of \(S(0)\)-factors have been obtained.

abstract

The differential cross section of the proton transfer in the \({}^{27}\)Al\((^{10}\)B, \({}^9\)Be)\(^{28}\)Si reaction at an energy of 41.3 MeV has been measured and analysed within the modified DWBA method. For the \({}^{28}\)Si(\({}^{28}\)Si\(^*)\to {}^{27}\)Al\(+p\) configurations, the new values of the squares ANCs \(C^2_{{}^{28}{\mathrm {Si}}}=1630\pm 300\) fm\(^{-1}\) and \(C^2_{{}^{28}{\mathrm {Si}}^*}=1590\pm 190\) fm\(^{-1}\), respectively, have been obtained.

abstract

To study Extensive Air Showers (EAS) at the Tien-Shan High Mountain Science Station (TSHMSS), a layout of an 8-channel Burst Detector (BD) was created. On the basis of the BD layout, a 24-channel BD prototype section is being developed to obtain preliminary experimental data. To evaluate the operation of the future prototype of the BD, the development of EAS was simulated at various interaction energies of the primary particle with the Earth’s atmosphere using the CORSIKA simulation package. Two combinations of interaction models for high-energy and low-energy interactions GHEISHA+QGSJET and UrQMD + EPOS have been chosen in this work. The simulation was carried out taking into account the height above the sea level parameter, the geomagnetic cutoff at a given geographical point (the parameters of the Earth’s magnetic field) of the prototype of the BD section with different types of primary particles, in a pre-selected energy range. After processing the output data using Python scripts, the type of particle, its energy, momentum, and coordinates at the observation level have been obtained, which are analyzed and optimized to compare the various received models.

abstract

In most collider experiments, the multiplicity of secondary particles is used to estimate the degree of collision centrality. It is assumed that the average multiplicity increases with an increase in the participating nucleons and the collision energy. In this work, a detailed study of the dependence of the multiplicity of secondary particles on the type of target, energy, and centrality of interaction for heavy (AgBr) and light (HCNO) target nuclei present in a nuclear emulsion (Em, NIKFI BR-2) was carried out using sulfur (S-32) projectiles at 3.7 \(A\)GeV and 200 \(A\)GeV and silicon (Si-28) projectiles at 14.6 \(A\)GeV. A comparative analysis of the multiplicity for these interactions showed that in the central interactions of S at 200 \(A\)GeV with heavy nuclei of the emulsion, the energy dependence of the multiplicity differs significantly from the other considered interactions.

abstract

The production cross sections and isomeric ratios of the cross sections of \((n,2n)\) reactions on \(^{198,200}\)Hg nuclei at a neutron energy of 14.1 MeV have been measured by the induced activity method. The isomeric ratios of the photo-neutron reaction yields (\(\gamma ,n\)) were also measured at the maximum bremsstrahlung energies of 25, 30, and 35 MeV. The experimental isomeric ratios are compared with the results of other works and the calculated results using the statistical model of the nucleus.

abstract

In this work, we present a new approach to produce isotopic distribution of fission fragments in relativistic heavy-ion collisions. We take into account the collective excitation after the production of the primary fragments and explain simultaneously the production of fission yields as well as the heavy and light fragments.

abstract

Elastic and inelastic channels of the \(d + {^{13}}\)C nuclear reaction at \(E(d)=14.5\) MeV are studied within the framework of the Coupled Channels method. Special attention is paid to the contribution of the inelastic channels to the elastic scattering channel. Preliminary results on the influence of the excited states 3.68 MeV and 7.54 MeV to the ground state in the target nucleus are shown. The transitions turned out to be having non-negligible contributions to the elastic scattering cross section.

abstract

The paper presents new experimental data on the double-differential and integral \((d,xd)\) reaction cross sections from the interaction of deuterons of 14.5 MeV energy with copper. The experiment was performed at the isochronous cyclotron of the Institute of Nuclear Physics, Kazakhstan. The experimental data were analysed within the framework of the TALYS‑1.9 calculation code. It is established that the obtained cross section is mainly formed by mechanisms of pre-equilibrium decay.

abstract

The differential cross sections of elastic and inelastic (\(1^{+}\), 0.718 MeV) scattering of deuterons on the \(^{10}\)B target were measured in the angular range of \(20^\circ \)–\(160^\circ \) in the center-of-mass system at an energy of 14.5 MeV. The analysis of the measured angular distributions was carried out by the method of coupled channels using the Fresco program. Two sets of optical potentials have been established that correctly describe elastic scattering data at energies of 11.8, 14.5, and 28 MeV. The value of the quadrupole deformation parameter \(\beta _{2} = 0.72\mathrm {\pm }0.1\) is extracted from the comparison of the calculated cross sections of inelastic scattering with experimental data. Within the error limits, the extracted \(\beta _{2}\) value agrees well with the results obtained from the analysis of protons, deuterons, and \(^{3}\)He scattered from the \(^{10}\)B target.

abstract

Reconstruction of trajectories of charged particles (tracking) is one of the actual problems in experiments in high-energy physics. In the tracking program developed by a team of authors of the Al-Farabi Kazakh National University and JINR to process data registered by detectors located in the magnetic field of the experimental setup SPD planned in a complex of the JINR NICA collider, an algorithm is proposed for sifting out false tracks that arise during neural network tracking. This algorithm is based on a threshold criterion that calculates the quality of the helical line fit to the samples that make up the candidate track recognized by the neural network. In this paper, that continues this research, a method is proposed to significantly speed up the algorithm to weed out false tracks by paralleling it. The results of a comparative analysis of the computational speedup when paralleling them with the condition of preserving the efficiency of track reconstruction are shown.

abstract

The energy spectra of protons and \(\alpha \)-particles are obtained for a wide range of angles in reactions of 22 MeV energy protons and \(^{59}\)Co nucleus. The experiment was performed at the isochronous cyclotron of the Institute of Nuclear Physics, Kazakhstan. The double-differential and integral cross sections of \((p,xp)\) and \((p,x\alpha )\) reactions were measured. Experimental results were compared with the TALYS-1.9 nuclear model code calculations. In general, the calculated spectra were in good agreement with the measured ones.

abstract

New differential cross sections of \(^{11}{\mathrm {B}}+{^{15}{\mathrm {N}}}\) scattering and \(^{11}{\mathrm {B}}(^{15}{\mathrm {N}},{^{14}{\mathrm {C}}}) ^{12}{\mathrm {C}}\) reaction were obtained at measurements on the U-200P cyclotron of the University of Warsaw at an energy of \(E_{^{15}{\mathrm {N}}}=43\) MeV. The contribution of the different mechanisms of the reaction was evaluated and the ANC squared value of \(46\pm 9\) fm\(^{-1}\) for the \(^{15}{\mathrm {N}}\rightarrow {^{14}{\mathrm {C}}}+p\) configuration of the \(^{15}{\mathrm {N}}\) ground state has been extracted from these data by the MDWBA analysis.

abstract

The problem of describing the nucleon pairing energy in nuclei was considered using a realistic nucleon–nucleon potential that reproduces the parameters of nucleon–nucleon scattering. Satisfactory agreement between the calculated and experimental values of the isotriplet nucleon pairing energies for even–even nuclei was obtained.

abstract

The study resonant scattering, the Thick Target Inverse Kinematics method was developed at the Heavy Ion Accelerator DC-60, Astana, Kazakhstan. In this paper, we report on the results of studies of \(^{20,21}\)Ne nuclei.

abstract

The experimental cross sections for elastic scattering of heavy \(^{15}\)N ions on a target of \(^{11}\)B isotopes were measured using an extracted beam at the DC-60 cyclotron at the Institute of Nuclear Physics (Astana, Kazakhstan). The beam energy of accelerated heavy ions was \({E_{\mathrm {lab}}} = 18.75\) MeV. The angular distribution of scattered ions was in the range from 10 to 50 degrees in the laboratory coordinate system. This paper provides a detailed description of the experimental procedure and a brief description of the equipment. The results of the study are experimental data on the interaction \(^{11}\)B(\(^{15}\)N, \(^{15}\)N)\(^{11}\)B and theoretical calculations for the process of elastic scattering \(^{15}\mathrm {N} + {^{11}}\)B. Theoretical calculations were performed within the framework of an optical model. The Woods–Saxon optical potential was used to analyze the experimental results of elastic scattering. As a result, good agreement was achieved between experimental data and theoretical predictions. The results of calculations within the framework of the theoretical model will be used for further analysis of experimental data on inelastic scattering of \(^{15}\)N by \(^{11}\)B.

abstract

According to the theoretical predictions, a mixed phase of the quark–gluon plasma must be formed in the energy range from 4 to 11 GeV. In this work, a joint study of the collisions of Au-197 projectiles at 10.6 \(A\)GeV and Pb-208 projectiles at 158 \(A\)GeV with heavy (AgBr) and light (HCNO) targets present in a nuclear emulsion (Em, NIKFI BR-2) was carried out. To search for non-statistical clusters of secondary particles, we analyzed both secondary particles emitted from the interaction region and fragments of the projectile-nucleus and target-nucleus. To study pseudo-rapidity correlations, the Hurst method was used. According to the behavior of the Hurst curve, events were divided into two types: correlated and uncorrelated. Events of various types differ significantly in the fragmentation of the projectile-nucleus, multiplicity of secondary particles, and pseudo-rapidity distribution. Some correlated-type events have an “anomalous” pseudo-rapidity distribution: two streams of secondary particles are formed with significantly different pseudo-rapidity. In such events, several multi-charged fragments are detected.

abstract

The main purpose of this work is to investigate the astrophysical S factor of the \(^7\)Be\((p,\gamma )^8\)B process at low energies. For this purpose, the new values of the asymptotic normalization coefficients for \(^7\)Be\(\,+\,p\to {}^8\)B with their uncertainties have been obtained from the analysis of the directly measured experimental astrophysical S-factors of the \(^7\)Be\((p,\gamma )^8\)B reaction in the off-resonance energy region with the modified two-body potential approach. The weighted values of the asymptotic normalization coefficients are used for extrapolation of the astrophysical S-factor for the \(^7\)Be\((p,\gamma )^8\)B reaction to low energies using the modified R-matrix approach. The new parameters of the resonances are obtained.