An end-window gas-flow proportional counter system, including an automatic precision sample changer, was used to measure the decay of radiations from two samples of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ and one of ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$. Comparison counts were taken on a ${}_{}{}^{36}{}_{}{}^{}\mathrm{Cl}$ standard, and the ratio of counts determined the decay. Points consisted of alternate 30-min counts on each sample and on the standard, totaling 30 h on each, and were taken at intervals of about one month. Based on 3 years of counting on the ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ source and on one of the ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ sources, and 1 year on the second ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ sample, half-lives were obtained as follows: ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$, 66.6(16) yr and ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$, 34.9(4) yr. The ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ value lies between the two most recently reported values. In the case of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ there are discrepancies with all three previous results including an Argonne accelerator mass spectroscopy value of 54.2(21) yr.

The decay of ${}_{}{}^{156}{}_{}{}^{}\mathrm{Pm}$ has been studied resulting in the first detailed information on the excited states of ${}_{}{}^{156}{}_{}{}^{}\mathrm{Sm}$. About 25 levels were found, of which two were γ-decaying isomers. The expected low-lying quadrupole vibrational levels could not be identified. The observed decay rates for β and γ transitions have enabled the classification of some levels, including the β-decaying ground state of ${}_{}{}^{156}{}_{}{}^{}\mathrm{Pm}$, in terms of specific two-quasiparticle states. The total beta-decay energy of ${}_{}{}^{156}{}_{}{}^{}\mathrm{Pm}$ was obtained as 5.155(35) MeV.

We shall show how the so-called Berry’s or quantum nonintegrable phase appears in the context of the time-dependent Hartree-Fock-Bogoliubov equations. It is shown that the right requantization of the time-dependent Hartree-Fock-Bogoliubov equations is achieved only when Berry’s phase is properly taken into account.

The SD pair condensate description of low-energy nuclear states is investigated in detail for ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$, using a shell model space of protons in the 1${\mathit{f}}_{7/2}$ orbit, and neutrons in the 2${\mathit{p}}_{3/2}$, 1${\mathit{f}}_{5/2}$, and 2${\mathit{p}}_{1/2}$ orbits. A direct method is employed in that eigenstates corresponding to low-energy levels are themselves analyzed to identify which are indeed well described in this manner. For those where such a description is appropriate, the emergence of dynamical symmetries in the mapped boson system, and in particular the identification of ‘‘mixed-symmetry’’ states, is also investigated. Results are satisfactory for the low-spin levels, and indicate an approximate U(6)⊃SO(6) dynamical symmetry.

The effects of uncertainties in the two-nucleon potential on the saturation properties of nuclear matter are studied. The nuclear matter energy is calculated by a recently developed ring-diagram method. The largest variations in the energy are due to ambiguities in the (off-shell) strength of the nuclear tensor force. For the six different realistic potential models considered, the total uncertainty is about 3 MeV for the saturation energy and 0.2 ${\mathrm{fm}}^{\mathrm{-}1}$ for the saturation Fermi momentum. This variation is substantially smaller than the corresponding one obtained in standard lowest-order Brueckner calculations (6 MeV, 0.3 ${\mathrm{fm}}^{\mathrm{-}1}$). The relevance of the tensor force for ring-diagram contributions is investigated systematically.

Within a quark-meson model of nuclear force with relativistic effects, taking into account the small component of Dirac spinor, the wave function of the relative motion for deuteron and the N-N effective interaction are calculated. The numerical results show that the small component of Dirac spinor is a significant quantity; the small component and the relevant color magnetic interaction directly cause the short-range soft repulsive core of nuclear force. The calculated effective potential and the NN-scattering phase shifts are in reasonable agreement with the experimental data.

The first three positive parity dipole states predicted by a phenomenological quadrupole-octupole boson Hamiltonian are extensively studied. Their coupling to the neighboring positive and negative parity states, due to the M1 and Eλ (λ=1,3) transitions, respectively, are considered. Special attention is paid to the lowest two states which are of collective M1 nature. The signature which distinguishes them from the M1 state describing the scissors mode is also discussed.

Both the field current identity and universal coupling imply that the isovector part of the anomalous magnetic moment of the nucleon, ${\mathrm{\kappa }}_{\mathit{v}}$, is equal to the tensor coupling of the ρ meson, ${\mathrm{\kappa }}_{\mathrm{\rho }}$. However, the empirical value of ${\mathrm{\kappa }}_{\mathrm{\rho }}$/${\mathrm{\kappa }}_{\mathit{v}}$ extracted through dispersion relation is 1.78. In this paper we show that a color dielectric model can explain in a natural way why the ratio ${\mathrm{\kappa }}_{\mathrm{\rho }}$/${\mathrm{\kappa }}_{\mathit{v}}$>1. We study a chirally invariant color dielectric model. We point out that a fractional power of the color dielectric function should be present in the quark-meson interaction term. The quark part of the ρ meson current, modified by this factor, is structurally different from the isovector part of the electromagnetic current. Both the magnetic-moment-like quantity, ${\mathrm{\mu }}_{\left(\mathrm{\rho }\right)}$, and the ρ-nucleon coupling constant, ${\mathit{g}}_{\mathrm{\rho }\mathit{N}\mathit{N}}$, are modified making ${\mathrm{\kappa }}_{\mathrm{\rho }}$=(${\mathrm{\mu }}_{\left(\mathrm{\rho }\right)\mathit{p}}$-${\mathrm{\mu }}_{\left(\mathrm{\rho }\right)\mathit{n}}$)(2M/${\mathit{g}}_{\mathrm{\rho }\mathit{N}\mathit{N}}$)-1 different from ${\mathrm{\kappa }}_{\mathit{v}}$ and, indeed, larger than ${\mathrm{\kappa }}_{\mathit{v}}$. The numerical value of the ratio ${\mathrm{\kappa }}_{\mathrm{\rho }}$/${\mathrm{\kappa }}_{\mathit{v}}$ is found to be 1.35, quite independent of the details of the model. It appears that some additional mechanism is needed to fit the value 1.78.

Symmetry-conserving higher order interactions in the SU(3) limit of the interacting boson model remove the degeneracy in the first β and γ band predicted by the original interacting boson model. It is possible, also for the fourth order interactions, to predict this removal using quantities describing odd-even staggering effects. Numerical tests confirm the influence of these interactions on the first bands of SU(3) nuclei.

We have investigated the structure of ${}_{}{}^{144}{}_{}{}^{}\mathrm{Nd}_{84}^{}{}_{}{}^{}$ within the framework of the cluster vibration model. Further, we have mapped, approximately, the cluster vibration model states into the proton-neutron interacting-boson model, with particular emphasis on the mixed-symmetry states, hindered transitions, quadrupole moment signs, and higher-angular-momentum pairs. The cluster vibration model $2^{+}$ (3) state and its properties correspond to the experimentally determined properties and map into the mixed-symmetry state of the proton-neutron interacting-boson model. We compare the calculations with recent in-beam (t,p) multiparameter (particle, gamma, gamma/conversion-electron) coincidence studies, which have established the positive-parity spectra up to 3 MeV. Some evidence is given for $0^{+}$ and $1^{+}$ levels associated with the $2^{+}$ (3) mixed-symmetry state.

We show that the exact K quantum number in the SU(3) limit of the interacting-boson model has a strong effect on the fluctuation properties: Pure sequences of a single K value have ${\mathrm{\Delta }}_3$ statistic close to the Gaussian overlap ensemble prediction while mixed sequences with combined K values are removed far from the Gaussian overlap ensemble because of K degeneracy, exceeding even the Poisson-ensemble prediction. Applying the extended interacting boson model to the realistic case of ${}_{}{}^{164}{}_{}{}^{}\mathrm{Er}$ nucleus, we have demonstrated that weak breaking of the K quantum number introduces a very rapid change in fluctuation properties towards those of a pure sequence.

Recent measurements of electron-deuteron elastic scattering at high momentum transfer have placed an empirical lower limit on the momentum transfer for the onset of asymptotic scaling. The implications that this limit has for the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(γ,p)n, ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(γ,d)${\mathrm{\pi }}^0$, and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(γ,d)H reactions will be discussed.

Lifetimes of states in ${}_{}{}^{79}{}_{}{}^{}\mathrm{Sr}$, populated by the ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$${(}^{28}$Si,2pn${)}^{79}$Sr reaction at 97 MeV, have been measured using the recoil distance Doppler shift technique. E2 transition strengths and transition quadrupole moments which are consistent with a deformation of β≃0.37 were obtained.

Excited state production has been measured for ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, and ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ fragments emitted in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$${+}^{12}$C reaction at E/A=8, 10, and 12 MeV. The use of reverse kinematics and a system with low rotational kinetic energy permitted a more direct test of the excited state method for temperature determination than had previously been possible. The results show that the population of excited states reflects the temperature expected from Fermi gas calculations at the appropriate excitation energy for the compound nucleus and is consistent with the temperature determined from the slope of the fragment spectra.

It is demonstrated that the naive expectation of ${\mathit{Z}}_{\mathit{T}}^2$ dependence of the cross section for reactions produced via Coulomb dissociation in heavy ions is modified substantially due to the ‘‘apparent’’ charge distribution. The deviations are shown to be important in predicting both the energy and the ${\mathit{Z}}_{\mathit{T}}$ dependence of the cross sections. The effect increases with Q value of a given dissociation channel; for a given Q value the deviation is larger for lower incident energy.

Stretched particle-hole states of a 0ħω (π${\mathit{d}}_{5/2}$,ν${\mathit{d}}_{5/2}^{\mathrm{-}1}$${)}_5^{+}$ type were observed as low-lying isolated peaks in the high-resolution (p,n) reactions on ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ at ${\mathit{E}}_{\mathit{p}}$=35 MeV. Angular distributions of the differential cross sections have been successfully interpreted, especially at large angles, or in high-momentum transfer regions (q∼2 ${\mathrm{fm}}^{\mathrm{-}1}$), by microscopic distorted-wave Born approximation calculations using shell-model wave functions and the M3Y interaction. No quenching of the (p,n) cross sections has been observed for these 0ħω stretched transitions in light nuclei.

We present results of a measurement of the beta-decay half-life of ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ using an ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ radioactive ion beam implanted in a Si detector. The half-life is found to be 840.3±0.9 ms.

Two controversial states considered to have a large alpha cluster strength, the $0^{+}$ state at 8.54 MeV and the $1^{\mathrm{-}}$ state at 11.7 MeV of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$, were examined in the ${(}^6$Li,d) reaction at E${(}^6$Li)=50 MeV. The 11.7-MeV state was scarcely observed, if at all, for ${\mathrm{\theta }}_{\mathrm{lab}}$=5–35°, and the angular distribution for the 8.54-MeV state was unlike that of an L=0 transition. These results indicate that both states are unsuitable candidates for the lowest states of the parity doublet band of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ in the alpha cluster model.

Angular distributions for the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$${+}^{13}$C elastic and inelastic scattering have been measured at a ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ bombarding energy of 50.46 MeV over an angular range from 10° to 170° c.m. Besides the ground state of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, the 3.68 MeV ${\mathit{J}}^{\mathrm{\pi }}$=3/$2^{\mathrm{-}}$ and the 7.55 MeV ${\mathit{J}}^{\mathrm{\pi }}$=5/$2^{\mathrm{-}}$ levels are strongly populated. The enhancement of the backward cross section is clear evidence that the process is dominated by the exchange of an α particle between two identical ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ cores. The experimental relative integrated cross sections are fairly well reproduced by distorted wave calculations using an α-cluster form factor and the shell-model spectroscopic strengths of Kurath.

Depth profiling results have indicated that the accepted value of 30±1 keV for the width of the 550 keV ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(p,γ${)}^{14}$N resonant reaction is incorrect. We have remeasured this width using implanted targets and have obtained a new value of 23±1 keV.