Том 87, № 3 (2024)

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.

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.

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.

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.

First results on

In the framework of the Standard Model, partial widths, double and single differential distributions for four-lepton decays

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.

The article studies the production of

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,

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.

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