Volume 30, Issue 6, November 1999
30(1999); http://dx.doi.org/10.1134/1.953120View Description Hide Description
The experimental and theoretical studies of lepton deep-inelastic scattering on nuclear targets are reviewed. The main problems which must be solved in analyzing the and dependences of the deep-inelastic cross sections are outlined. Several of the models proposed for studying the contribution of nuclear effects to the structure functions are analyzed. A relativistic field-theoretical approach to studying lepton deep-inelastic scattering on very light nuclei is developed. The modifications of the nucleonstructure in D, and are studied for the first time within a unified approach. It is found that the modifications evolve in a manner completely different from that observed earlier for heavy nuclei. In particular, it is found that the pattern of modifications represented in terms of the ratios is determined by the values (D/N), 0.16 and 0.08 These results allow the definition of the class of modifications of the bound-nucleon structure and the introduction of the unit of nucleon-structure modification. Theoretical justification of the concept of two-stage evolution of the nucleonstructure as a function of the first stage occurring for and the second for is also obtained. The long-standing problem of the nature of the EMC effect is explained as a modification of the nucleonstructure in the field of the nuclear forces in a three-nucleon bound system.
30(1999); http://dx.doi.org/10.1134/1.953121View Description Hide Description
The hypothetical existence of η nuclei, including superlight ones is discussed in the light of the new data and the nuclear model with an optical potential. The quasifree photoproduction of η mesons on light nuclei is used as the basis for constructing a systematic model of η-nucleus photoproduction in reactions The dependence of the cross sections for such reactions on the main proposed properties of η nuclei is discussed, along with the final-state interaction for incident γ energies in the range from threshold to 1 GeV.
30(1999); http://dx.doi.org/10.1134/1.953122View Description Hide Description
The present study is the second part of a review devoted to the properties of light neutron-rich nuclei. It focuses on the structure of neutron-rich isotopes of light elements with (the isotopes and The results published up to January 1999 are quoted. The latest results have been obtained by using exotic radioactive targets such as and and also radioactive beams. Information is given which sheds light on the properties of light nuclei close to the neutron dripline. Unusual properties of such nuclei have been observed (neutronhalo,neutron skin, energy-level inversion, and so on). The experimental data are compared with calculations carried out within the existing theoretical models.
30(1999); http://dx.doi.org/10.1134/1.953123View Description Hide Description
The experimental techniques and results on delayed nuclear fission are reviewed. In this process the daughter nucleus produced in capture of the parent nucleus undergoes fission from an excited state. The main experimental results are described. The qualitative theory of the process is discussed. The possibility of determining the fission barrier heights from the experimental data on delayed fission, in particular, on the probability of delayed fission, is studied. Special attention is given to the techniques of measuring the main characteristics of the delayed-fission process.
30(1999); http://dx.doi.org/10.1134/1.953124View Description Hide Description
The classical and modern methods and the results of analytic studies of the structure of the stationary Schrödinger and Faddeev equations and their solutions describing states of three-particle systems with central and -wave interactions are reviewed. Special attention is given to the angular analysis of these equations and the exact transformation laws of the three-particle coordinates, operators, basis functions, and wave functions under cyclic permutations of the particles. The problem of spurious solutions is analyzed.