The neutron spectroscopy of the $\beta$-delayed neutron decay of ${}^{14}$Be has been investigated. A strong neutron group, which accounts for much of the $\beta$-decay yield and could explain the discrepancy in total neutron branching ratio found in a previous experiment, was observed. We found that the total width of the final state for this transition is $60\pm 5\pm 6$ keV, and the measured half-life of the ${}^{14}$Be $\beta$ decay was $4.29\pm 0.18$ ms. The limits on the branching ratio and log$\mathrm{ft}$ value determined for this group are compared with the earlier work and the results of a shell-model calculation.

Low-spin states in ${}^{124,126,128,130}\mathrm{Ba}$ fed by the $\mathrm{EC}/{\beta }^{+}$ decay of their La parents have been investigated by means of the γ-γ angular correlation measurement coupled with an isotope separator on-line. The spin of the first excited $0^{+}$ states ${(0\mathrm{}}_2^{+})$ were unambiguously established, and higher-excited $0^{+}$ states were newly identified. The energy of the $0_2^{+}$ state in ${}^{124}\mathrm{Ba}$ previously assigned was revised upward. Resultingly, the level energy of the $0_2^{+}$ state in neutron-deficient Ba nuclei takes a minimum at $N=72\mathrm{}$ and then gradually increases toward neutron midshell $\mathrm{}(N=66\mathrm{}),$ while the level energy of the $0_3^{+}$ state rapidly decreases with decreasing neutron number. From an extrapolation of these $0^{+}$ energies, it is highly expected that the energy relation between the $0_2^{+}$ and $0_3^{+}$ state would invert at ${}^{122}\mathrm{Ba}$ or at more deformed Ba nuclei. This energy inversion is interpreted as the evolution of the $0_2^{+}$ state in γ-soft nuclei toward the two-phonon γ-vibrational $0^{+}$ state in axially-symmetric deformed nuclei, while the $0_3^{+}$ state toward the β-vibrational $0^{+}$ state.

${}^{11}$Li and ${}^6$He are described as three-body systems using different approaches. We compare our technique, based on a density-dependent, cutoff, contact interaction between the valence neutrons, with a Faddeev approach which is based on realistic interactions. The ground state properties of a weakly bound two-neutron halo are described fairly well once the contact interaction has been adjusted and calibrated to produce a realistic scattering length and effective range.

The energies and matter densities of finite nuclei under radial compression are predicted by using a constrained Hartree-Fock method with the $\Delta$ degree of freedom included. The results are presented for ${}^{90}$Zr in a calculation within a model space of seven major oscillator shells. The main feature of this calculation is that the effective baryon-baryon interactions associated with the $\Delta$ are evaluated within a $G$-matrix approach based on a coupled-channel $\mathrm{NN}\oplus N\Delta \oplus \pi \mathrm{NN}$ model that can describe the $\mathrm{NN}$ data up to 1 GeV. It is found that as the nucleus is compressed to about 2–3 times of the ordinary nuclear density, the $\Delta$ component is sharply increased to about 10% of all baryons in the system. This result is consistent with the values extracted from relativistic heavy-ion collisions.

We examine the nuclear medium effect on charge symmetry breaking (CSB) caused by isospin mixing of two neutral vector mesons interacting with nucleons in the nuclear medium. Isospin mixing is assumed to occur through the transition between isoscalar and isovector mesons. We use a quantum hadrodynamic nuclear model in the mean-field approximation for the meson fields involved. We find that (i) charge symmetry is gradually restored in nuclear matter in $\beta$ equilibrium as the nucleon density increases; (ii) when the system departs from $\beta$ equilibrium, CSB is much enhanced because the isospin mixing depends strongly on the nucleon isovector density; (iii) this leads to the symmetry energy coefficient of $32$MeV, of which more than 50 percent arises from the mesonic mean fields; (iv) the Nolen-Schiffer anomaly regarding the masses of neighboring mirror nuclei can be resolved by considering these aspects of CSB in nuclear medium.

We use the shell model Monte Carlo method to calculate complete $0f1p$-shell response functions for Gamow-Teller (GT) operators and obtain the corresponding strength distributions using a maximum entropy technique. The approach is validated against direct diagonalization for ${}^{48}$Ti. Calculated GT strength distributions agree well with data from $\mathrm{}(n,p)\mathrm{}$ and $\mathrm{}(p,n)\mathrm{}$ reactions for nuclei with $A=48\mathrm{}$–64. We also calculate the temperature evolution of the GT${}_{+}$ distributions for representative nuclei and find that the GT${}_{+}$ distributions broaden and the centroids shift to lower energies with increasing temperature.

Experimental information on the energy distribution of states in the lowest lying configurations of selected odd-odd nuclei just beyond ${}^{208}$Pb is summarized. In ${}^{210}$Bi the $\pi {0h}_{9/2}\otimes \nu {1g}_{9/2}$ configuration and other low lying configurations all have the inverted parabola shape in a plot of energy versus spin. When additional pairs of protons and/or neutrons are added, leading to heavier odd-odd nuclei, the inverted parabola becomes more compressed. Before these trends can be completed, however, quadrupole-octupole deformation sets in. Using the generalized intermediate coupling model, it is possible to reproduce these experimental trends and then to carry them to completion in the reversed parabola (of energy versus spin) resulting from the configuration $\pi {0h}_{9/2}\otimes \nu {(1g}_{9/2}{)}^{-1}$ or $\pi {(0h}_{9/2}{)}^{-1}\otimes \nu {1g}_{9/2}.$

We study the nucleus ${}^{176}\mathrm{Lu}$ within the framework of the particle-rotor model. The aim of this study is to obtain information on the residual neutron-proton interaction in doubly odd deformed nuclei. To this end, both zero-range and finite-range interactions are considered with particular attention focused on the role of the tensor force, which is still a controversial issue. A detailed comparison of the calculated results with experimental data provides clear evidence of the importance of the tensor-force effects.

We use the Gorkov formulation of the Dirac-Hartree-Fock-Bogoliubov approximation to nuclear pairing to study the ${}^1{S}_0$ nucleon-nucleon correlations in nuclear matter. We find the short-range correlations of the ${}^1{S}_0$ pairing fields to be almost identical to those of the two-nucleon virtual state. We obtain mutually consistent results for the pairing fields, using several different sets of effective interaction parameters, when we demand that each of these sets places the virtual-state pole at its physical location.

We evaluate the spreading width of the giant multipole resonances at finite temperature using the discontinuity in the second derivative of the Green’s function of the vibrational boson, in the Matsubara’s framework. Our method allows us to identify the processes that contribute to the spreading width in terms of the Feynman diagrammatic expansion of the full boson propagator. We have applied the calculation of the spreading width to the ${}^{208}\mathrm{Pb}$ and the ${}^{90}\mathrm{Zr}$ obtaining an increment of the spreading width with the temperature. We have not reached any saturation of the spreading width increment, at least up to the temperature of our calculation.

Isoscalar and isovector monopole responses of Ca isotopes towards drip lines are studied in comparison with those of stable nuclei, ${}^{40}\mathrm{Ca},$ ${}^{90}\mathrm{Zr},$ and ${}^{208}\mathrm{Pb},$ using the self-consistent Hartree-Fock calculation plus the random phase approximation with Skyrme interactions. Including simultaneously both the isoscalar and the isovector correlation the RPA response function is calculated in the coordinate space so as to take properly into account the continuum effect. The distribution of the monopole strength is much affected by the presence of the low-energy threshold strength in both proton and neutron drip line nuclei, while the isoscalar monopole strength is concentrated in one giant peak in the heavy β-stable nucleus ${}^{208}\mathrm{Pb}.$ It is found that in drip line nuclei the transition density and the displacement field of protons are very different from those of neutrons, especially around the nuclear surface. The relation between the compression modulus of the nuclear matter $K_{\mathrm{nm}}$ and that of finite nuclei $K_A$ is also discussed by using the energy moments estimated in RPA.

We study here hot nuclear matter in the quark meson coupling model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar and vector mesons. The equation of state of nuclear matter including the composite nature of the nucleons is calculated at finite temperatures. The calculations are done taking into account the medium-dependent bag constant. Nucleon properties at finite temperatures as calculated here are found to be appreciably different from the value at $T=0.\mathrm{}$

Properties of the ground state and first $2^{+}$ state of a large number of even-even nuclei in the Xe-Ba region have been calculated using a simple version of cranked Hartree-Fock-Bogoliubov model. The parameter set used has been obtained by fitting the ground state properties of some of the nuclei in this region. The sensitivity of the results to the choice of parameters has also been tested in a few cases. The shape rigidity of the nuclei in this mass region has been studied by generating energy contours in the ${\beta }_2$-$\gamma$ plane. Influence of the hexadecapole deformation on nuclei having flat energy surfaces in the $\gamma$ direction has been examined. Higher angular momentum states also (up to $6^{+}$ or ${10}^{+})$ have been calculated in some of the nuclei to study the evolution of shape and nature of alignment with increasing spin.

Differential cross sections for quasielastic electron scattering on ${}^{40}$Ca have been measured at laboratory scattering angles of 45.5$°$, 90$°$, and 140$°$ with bombarding energies ranging from 130 to 840 MeV. Transverse and longitudinal response functions have been extracted for momentum transfers from 300 to 500 MeV/$c$. Contrary to some previously reported results, the total observed longitudinal strength agrees with the relativistic Fermi gas prediction to within $\pm$18%.

The cross section of the $p(n,\gamma )d$ reaction was directly measured for the first time at $E_n$=550 keV, where the theoretical $E1\mathrm{}$ transition strength is comparable to the $M1\mathrm{}$ strength. It was determined accurately to be 35.2 (24) μb, and it agrees with the theoretical one which includes the meson-exchange currents. In this work, a prompt discrete γ-ray detection method combined with a pulsed neutron beam and a newly developed Monte Carlo code was essential to obtain an accurate cross section.

Using the 4$\pi$ light charged-particle detector DIAMANT in combination with the $\gamma$-ray spectrometer EUROGAM II, the decay of the ${}^{90}$Ru compound nucleus via the $p\alpha$ channel was studied. These nuclei were produced at an excitation energy of 54.9 MeV and with a maximum angular momentum of 37$ħ$ by the 120 MeV ${}^{32}$S + ${}^{58}$Ni reaction. The measurement of the energy of the two particles allowed the determination of the energy distribution of the entry states. A particular behavior of the sharing of the available energy between the two particles was found: For increasing values of the entry-state energy, the mean energy for protons remains almost constant while for alpha particles it decreases. This behavior is well reproduced by the evaporation code LILITA_N95. The physics underlying the decay is discussed in the framework of the statistical model which predicts a strong correlation between the excitation energy and the angular momentum of the evaporation residue. This result encourages the use of the $p\alpha$ channel to select the excitation energy and the angular momentum of the evaporation residue for superdeformed band studies.

Inelastic scattering of ${}^{40}$Ca on ${}^{40}$Ca at 50 MeV/nucleon has been measured in coincidence with light charged particles detected over a large angular domain. The giant resonance region of the inelastic spectrum is shown to be dominated by the isoscalar giant quadrupole resonance. The characteristics of the emitted protons allow us to separate four reaction mechanisms contributing to the high excitation energy region of the inelastic spectrum (E${}^{*}>$ 30 MeV): pickup breakup, knockout, inelastic scattering to high-lying target states, and a new mechanism responsible for the emission of fast-moving protons. A sizable direct decay branch towards hole states of ${}^{39}$K is measured for the giant quadrupole resonance in ${}^{40}$Ca. Evidence is given for the excitation of the two-phonon giant quadrupole resonance, characterized by its direct decay scheme. The energy and width of this two-phonon state are in agreement with a harmonic picture for collective nuclear excitations.

Light charged particles from ${}^{18}{\mathrm{O}+}^{100}\mathrm{Mo}$ reactions at 200 MeV bombarding energy have been measured in singles and in coincidence with high-energy γ rays $(>~10\mathrm{MeV})$ produced primarily in the decay of the giant-dipole resonance. Particle spectra are analyzed in terms of a moving source fit to decompose preequilibrium and evaporative components. Preequilibrium particle multiplicities and energies indicate a reduction in the compound nucleus excitation energy of approximately 20% and a loss of mass of approximately three mass units relative to complete fusion. The energy lost to preequilibrium emission is shown to affect significantly the strength, width, and centroid energy of the giant-dipole resonance deduced from fits to high-energy γ-ray emission spectra. Evaporation residue cross sections were measured for the same reaction from 100 to 217 MeV in order to determine the fusionlike event cross section.

The isovector 0${}^{+}$ to 0${}^{-}$ transition in the ${}^{16}$O${\mathrm{}(p,n)\mathrm{}}^{16}$F (g.s.) reaction was studied at 79 MeV. Differential cross sections were extracted for the transitions to the low-lying complex of 0${}^{-}$, 1${}^{-}$, 2${}^{-}$, and 3${}^{-}$ states in ${}^{16}$F at 12 laboratory angles from 0.3$°$ to 63$°$ which correspond to momentum transfers from 0.21 to 2.0 fm${}^{-1}$. An energy resolution of 140 keV (FWHM) was achieved which was sufficient to separate the yields for each of these four states. Distorted-wave-impulse-approximation (DWIA) calculations were performed and compared with the extracted cross sections for these four transitions. The DWIA calculations with the effective interaction of Franey and Love provide a good description of the experimental measurements for the 0${}^{-}$ transition at low momentum transfer, but overestimate the data at larger momentum transfer. The experimental results for the 1${}^{-}$, 2${}^{-}$, and 3${}^{-}$ transitions are described reasonably well by the DWIA calculations.

The production rates per Ξ via the ${}^{12}\mathrm{C}+{\Xi }^{-}$-atomic states are investigated for the ${}_{\Lambda \Lambda }^{12}\mathrm{Be}+p,$ ${}_{\Lambda \Lambda }^{12}\mathrm{B}+n,$ ${}_{\Lambda \Lambda }^{11}\mathrm{Be}+d,$ ${}_{\Lambda \Lambda }^{10}\mathrm{Be}+t,$ ${}_{\Lambda \Lambda }^9\mathrm{Li}+\alpha ,$ ${}_{\mathrm{\Lambda }\mathrm{\Lambda }}^6{\mathrm{H}\mathrm{e}+}^7\mathrm{Li},$ ${}_{\mathrm{\Lambda }\mathrm{\Lambda }}^5{\mathrm{H}+}^8\mathrm{Be},$ ${}_{\mathrm{\Lambda }}^9{\mathrm{B}\mathrm{e}+}_{\mathrm{\Lambda }}^4\mathrm{H},$ ${}_{\mathrm{\Lambda }}^8{\mathrm{L}\mathrm{i}+}_{\mathrm{\Lambda }}^5\mathrm{He},$ and ${}_{\Lambda }^{12}\mathrm{B}+\Lambda$ channels (including their excited channels) within the frame of the doorway double-Λ hypernuclear picture (direct reaction picture). We found that in the stopped ${\Xi }^{-}$ reaction (1) the excited double-Λ hypernuclear states for ${}_{\Lambda \Lambda }^{12}\mathrm{B},$ ${}_{\Lambda \Lambda }^{12}\mathrm{Be},$ and ${}_{\Lambda \Lambda }^{11}\mathrm{Be}$ are produced more strongly than other double-Λ hypernuclei, and (2) the production rates per Ξ depend considerably on the atomic orbital angular momentum of the ${\Xi }^{-}$ particle absorbed into nuclei. The calculated production rates per Ξ are discussed in comparison with the KEK-E176 experimental data.