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[en] The properties of neutron-star matter up to the appearance of hyperons are calculated with the aid of Skyrme potentials. The conditions for the appearance of Λ hyperons in matter and values of the density at the point of their appearance are analyzed for various parametrizations of nucleon-nucleon and hyperon-nucleon interactions. The dependence of the results on the magnitude of density-dependent forces, the degree of nonlocality, the behavior of the symmetry energy, and incompressibility of nuclear matter is examined.
[en] Pairing forces between nucleons in an atomic nucleus strongly influence its structure. One of the manifestations of pair interaction is the ground state multiplet (GSM) formation in the spectrum of low-lying excited states of even–even nuclei. The value of GSM splitting is determined by the value of pair interaction of nucleons; for each isotope, it can be estimated on the basis of experimental nuclear masses. The quality of this estimate is characterized by the degree of reproduction of GSM levels in the nucleus. The GSM systematics in even–even nuclei with a pair of identical nucleons in addition to the filled nuclear core is considered on the basis of delta interaction
[en] For the stable silicon isotopes 28Si and 30Si, the energies and occupancies of single-particle states of the 1d2s shell are determined by analyzing the combined data for the nucleon stripping and pickup reactions. From the results of analysis and the available experimental data, the variation of the 1d2s proton-shell structure with increasing neutron number for the silicon isotopes with A = 26–34 is discussed.
[en] The cross section and angular distributions of fission fragments have been measured for the compound nucleus 224Th produced in the reaction 16O+208Pb at four energy values in the range from 5 to 15 MeV below the fusion barrier calculated in terms of the Bass model. The performed measurements allowed one for the first time to obtain data for the region of interaction of heavy ions with nuclei characterized by the cross section being by 8 orders of magnitude lower than the geometric cross section. It can be seen that at the energy of oxygen ions of up to Elab≤82 MeV, account should be taken of the contribution made by the lowest vibration states of interacting partners. The measured angular distributions of fission fragments are in agreement with the calculations performed within the framework of the standard statistic transition state model for the saddle point. The data do not support the hypothesis that deep-subbarrier reactions are characterized by fission fragments showing anomalously high anisotropy. However in the investigated energy range there is a plateau characterized by the relation W(180 deg.)/W(90 deg.)=1.2 in the angular anisotropy of fission fragments. This implies that the available angular packet of harmonics, which govern the production cross section of a compound nucleus, is approximately the same
[en] The results obtained by measuring the angular and energy distributions of gamma rays produced in reactions induced by the inelastic scattering of 14.1-MeV neutrons on 27Al nuclei are presented. The respective measurements were performed by the tagged-neutron method in a beam from the ING-27 compact neutron generator. The angular distributions were obtained for gamma rays emitted from the 844-keV 1/2+, 1015-keV 3/2+, 2212-keV 7/2+, and 3004-keV 9/2+ states of 27 Al nuclei.
[en] The ground state multiplet structure for nuclei over the wide range of mass number A was calculated in δ-approximation and different mass relations for pairing energy were analysed in this work. Correlation between the calculated multiplet structure and experimental data offers a guideline in deciding between mass relations for nucleon pairing.
[en] The results obtained by measuring the angular and energy distributions of gamma rays originating from the inelastic scattering of 14.1-MeV neutrons by carbon and oxygen nuclei are presented. The measurements in question were performed by the tagged-neutron method in a beam of an ING-27 standard portable neutron generator. The angular distributions of gamma rays emitted by the 2+ state of 12С at 4.43 MeVand the 3− state of 16O at 6.13 MeV were obtained.