[en] A comparison between the semi-classical approximation and the full quantum calculation with a complex absorbing potential is made with a model of the fission of ²⁵⁸Fm. The potential barrier is obtained with the constrained Skyrme HF+BCS theory. The life-time obtained by the two calculations agree with each other, the difference being only 25% approximately. This difference could be attributed to the assumption of 'harmonicity' for the confining potential or to the accuracy of the semi-classical approximation. (authors)

[en] A study of direct neutron induced reactions off spherical nuclei is given in terms of a folding model. Matter densities stemming from the Random Phase Approximation (RPA), implemented with the Gogny D1S force are used to provide the relevant coupling potentials. The impact of rearrangement corrections on cross sections is studied for direct inelastic nucleon scattering off ¹⁶O and ²⁰⁸Pb. The rearrangement correction to calculated cross sections is shown to strongly depend on the incident energy and on the excitation multipolarity. (authors)

[en] Nuclear transmutation of long-lived fission products (LLFP) ejected from nuclear reactor plants is one of the most important tasks on nuclear physics and engineering. The experiments with the radiative target are limited, due to the high radioactivity and chemical property of the target. In consequence, the nuclear reaction data for LLFP are insufficient. In this work, we propose a feasible method to obtain the data for radiative targets using inverse kinematics and simulate specific systems to evaluate the thick-target yields of the nuclear transmutation reactions for LLFP. (authors)

[en] We formulate the absorbing boundary condition (ABC) in the coupled-rearrangement-channels variational method (CNR) for the three-body problem. The absorbing potential is introduced in the system of the identical three-bosons, on which the boson symmetry is explicitly imposed by considering the rearrangement channels. The resonance parameters and the strength of the monopole breakup are calculated by the CRCVM + ABC method, and the results are compared with the complex scaling method (CSM). We have found that the results of the ABC method are consistent with the CSM results. The effect of the boson symmetry, which is often neglected in the calculation of the triple α reactions, is also discussed. (authors)

[en] Clusters are quite important at various situations in heavy-ion collisions. Antisymmetrized molecular dynamics was improved to take into account the correlations to form light clusters, such as deuterons and α particles, and light nuclei composed of several clusters. The momentum fluctuations of emitted particles are also taken into account by a simple method. Formation of fragments and light clusters in a wide range of heavy-ion collisions was well described with a single set of model parameters. Fragmentation in a proton induced reaction was also well reproduced by introducing cluster correlations. Calculated results demonstrate strong impacts of clusters in various observables including those usually regarded as probes of the density dependence of symmetry energy. (authors)

[en] We investigate the continuum-discretized coupled-channel analysis to the integrated elastic and inelastic scattering cross sections for ^6,7Li + n reactions. We used the Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction and optical model potential at incident neutron energies below and above 10 MeV, respectively. The calculated elastic and inelastic scattering cross sections with observed incident energies are almost in good agreement with experimental and evaluated data. (authors)

[en] In observed neutron resonances, long believed to be a form of quantum chaos, regular family structures are found in the s-wave resonances of many even-even nuclei in the tens keV to MeV region [M. Ohkubo, Phys. Rev. C 87, 014608(2013)]. Resonance reactions take place when the incident de Broglie wave synchronizes with the Poincare cycle of the compound nucleus, which is composed of several normal modes with periods that are time quantized by inverse Fermi energy. Based on the breathing model of the compound nucleus, neutron resonance energies in family structures are written by simple arithmetic expressions using S_n and small integers. Family structures in observed resonances of ⁴⁰Ca+n and ³⁷Cl+n are described as simple cases. A model for time quantization is discussed. (author)

[en] The neutron capture cross section of ⁸⁹Y was measured by the time-of-flight method in an energy range from 15 to 100 keV. A pulse-height weighting technique was applied to derive the capture yield. The absolute cross section was determined based on the standard reaction ¹⁹⁷Au(n, γ)¹⁹⁸Au reaction. The neutron capture γ-ray spectrum was derived by unfolding the pulse-height spectrum with detector response functions. (authors)

[en] We define the optimal shape which fissioning nuclei attain just before the scission and calculate the deformation energy as function of the mass asymmetry at the scission point. The calculated deformation energy is used in quasi-static approximation for the estimation of mass distribution, total kinetic and excitation energy of fission fragments, and the total number of prompt neutrons. The calculated results reproduce rather well the experimental data on the position of the peaks in the mass distribution of fission fragments, the total kinetic and excitation energy of fission fragments. The calculated value of neutron multiplicity is somewhat larger than experimental results. The saw-tooth structure of neutron multiplicity is qualitatively reproduced. (author)

[en] By applying the particle-number projection to the finite-temperature Bardeen-Cooper-Schrieffer (Bcs) theory to the state densities in the rare-earth nuclei and comparing its results to the shell model Monte Carlo (SMMC) ones, we investigate effects of the particle-number conservation on the collective enhancement factor for the state densities. Once we restore the particle-number conservation, the rapid decay of vibrational enhancement disappears. This suggests that the vibrational collectivity may survive up to higher energy and the relevant enhancement factor is insensitive to the excitation energy. (authors)