[en] A new group of spherical single-particle potentials applicable to a wide nuclidic region are obtained. The central component of each potential is a five-parameter refinement of the Woods-Saxon potential including two new parameters, of which one parameter governs the behavior at large distances and the other produces a dip in the surface region. These five potential parameters as well as the parameters in the spin-orbit component are assumed to vary smoothly with Z and N. In evaluating the Coulomb energy of a single proton, occasional deviations of that proton from the single-particle state to more complicated states are taken into account by including an adjustable parameter. The adjustable parameters introduced are fixed by comparison with experimental data of single-particle levels in the vicinities of 15 doubly magic or magic-submagic nuclides ranging from ⁴He to ²⁰⁸Pb, and a reasonable agreement with experiment is obtained

[en] Nuclear masses and β-decay half-lives are discussed from a theoretical viewpoint. In particular, a mass formula which was recently proposed by Uno and Yamada is explained in some detail. One of the main characteristics of this formula is that it gives not only the mass values but also their theoretical errors. As for the β-decay, it is pointed out that incorporation of some shell effects into the gross theory greatly improves the predictive power of the theory. (author)

[en] A nuclear mass formula is constructed which is composed of two parts, one describing the general trend of the masses as a function of Z and N and the other representing deviations of individual masses from this general trend. These deviations are referred to as shell energies in a broad sense. The shell energies of spherical nuclei are calculated with use of a spherical single-particle potential. The shell energies of deformed nuclei consist of intrinsic shell energies and average deformation energies. The intrinsic shell energy of a deformed nucleus is calculated from the shell energies of appropriate spherical nuclei by treating the deformed nucleus as a superposition of spherical nuclei. The obtained mass formula is applicable to any nucleus with Z≥2 and N≥2 . The root-mean-square deviation from experimentally known masses is 0.68 MeV

[en] The first half of the report focuses on atomic mass formulas which have been developed by the author and his coworkers for accurate representation of the mass of various nuclides at their ground state. The one most frequently used by them is the Uno-Yamada Formula, which consists of two parts representing the gross behavior and the fluctuations due to each nuclide, or so called shell effect. The latter part is the sum of a proton shell term and a neutron shell term, and may be constant or linear depending on the form of the shell terms. Two new formulas have been derived by incorporating the effect of proton-neutron interaction into the above-mentioned constant-type formula. One of them is different from the constant-type Uno-Yamada Formula in that the shell effect part contains a proton-neutron interaction term. Modification is also made to take into account the coulombic energy. The second half of the report addresses the β-decay gross theory. A modified β-decay gross theory is presented, in which improvements are made to reflect the effect of the UV factor and to meet the sum rules related with the Fermi transition. The monoparticle intensity function is also improved by taking into account solutions of many-body problems related with the sum rules. (N.K.)

[en] The rates of β-decay and electron capture are calculated for nuclear excited states on the basis of the gross theory of β-decay. Emphasis is placed on the difference between the decays of the ground and excited states, and graphs are given to show the differences quantitatively. Astrophysical implications of these calculations are discussed. (auth.)

[en] A density-dependent nuclear mass formula is constructed with consideration for cluster formation at low densities and causality at high densities. This formula combined with the nuclear elasticity is used to calculate the energies of isoscalar E0 giant resonances. The values of the parameters in the formula are determined from comparison with experimental data on these resonance energies and the ground-state masses and sizes. This formula is approximately equal to the Weizsacker-Bethe formula as far as the ground-state masses are concerned, and gives a nuclear incompressibility modulus which is considerably smaller than that obtained without the nuclear elasticity. (author)

[en] The mass of nuclei far from beta stability domain is discussed from various aspects. Examples of the measurement of Q β values of beta decay up to unstable domain are rare. The measured data for A = 182 shows that the difference among mass formulas became large suddenly toward unstable domain. Beta intensity function is important function of beta decay. The function has some relation with Q β value, therefore the dependence on Q β was investigated. However, it is hard to say any conclusion for this dependence at present. The phenomena of delayed ventron emission has some relation with atomic mass through Q β value and separation energy S. most of Q β and S are still unknown, and further investigation is expected. The mass of fragments in nuclear scission plays important role in nuclear fission, and affects on the partial half-life of decay to said fragments. Recently, mass formula is expressed as a function of 1N-Zl, and as the range of N(z) is wider, the dependence of the mass formula on 1N-Zl can be decided better. The accuracy of measurement for the mass of very unstable nuclei is estimated to be about 0.5 MeV, and the measurement with the accuracy of 0.2 MeV will be good enough. (Kato, T.)

No abstract available

[en] The distribution function of the particle occupation probability in the momentum space is investigated by the cluster variation method. The distribution function calculated in the two-body cluster approximation often gives unreasonably too many particles jumping out of the degenerate state. A new condition is introduced to suppress the excitation of too many particles. The condition is applied to liquid helium-4 and neutron matter. Numerical results show that the condition regulates the behavior of the momentum distribution function, and is useful to avoid an unnatural kinetic energy. (author)

[en] General properties of nuclear β-decay are discussed on the basis of the gross theory. It is demonstrated that the agreement with experimental data is greatly improved by a good choice of the Q-values and by inclusion of the shell effects. Various aspects of the shell effects are discussed in considerable detail. Based on a fairly general single-particle scheme, several systematics are derived for the β strength functions and half-lives. (auth.)