Further evidence for the presence of an anomaly in binding energies for the ‘‘island of inversion’’ centered at Z=11, N=21 is obtained by comparison of shell-model calculations to experiment. The calculations were done with a shell-model interaction that is applicable to nuclei with active valence nucleons in both the (1s,0d) and (0f,1p) major shells. This interaction is described in detail as are its predictions for binding energies and energy spectra of Z=8–20, N=18–25 nuclei. These calculations provide the background for the exploration of the ‘‘island of inversion.’’ The extent of the ‘‘island’’ and the magnitude of the anomaly is explored by calculating the binding energies of 2ħω excitations of neutrons from the (1s,0d) shell to the (0f,1p) shell relative to the 0ħω ground state. The reason why mixed (0+2)ħω calculations are not considered reliable is addressed. Truncation schemes and a weak-coupling approximation are used to extend the range of the calculations. It is found that for Z=10–12, N=20–22 (and possibly N>22) nuclei the lowest 2ħω state is more bound than the 0ħω ground state. The role of odd n nħω excitations is considered and it is found that the 1ħω ground state always lies below that of 3ħω, and for N=19, 21, and 23, the lowest 1ħω state is in close competition with 2ħω for the lowest binding energy. Collectivity is considered via E2 observables and energy spectra for the 2ħω ground-state bands. The reason for the existence of the ‘‘island’’ is discussed.

Electric monopole transitions between low lying $0^{+}$ states in ${}_{}{}^{110}{}_{}{}^{}\mathrm{Cd}$ have been studied by means of electron internal conversion and gamma spectroscopy. Values or upper limits for the ratio ${\mathit{X}}_{\mathit{i}\mathit{j}\mathit{f}}$ between the B(E0;$0_{\mathit{i}}^{+}$→$0_{\mathit{j}}^{+}$) and B(E2;$0_{\mathit{i}}^{+}$→$2_{\mathit{f}}^{+}$) reduced transition probabilities have been determined. The results are discussed in the frame of the proton-neutron-interacting-boson configuration mixing model.

We have studied the levels of ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$ populated in the beta decay of ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ by gamma-ray spectroscopy, which included Compton-suppression gamma-ray spectra of ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ sources that were continuously eluted of the ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$ daughter activity using ion-exchange chromatographic techniques. The study of the gamma-ray deexcitation of the low-energy levels was completed by a measurement of the low-energy gamma-ray spectrum following thermal neutron capture on ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$. Also, we have performed calculations using the interacting-boson-fermion-fermion model. When we compare the model predictions with the levels and their properties, which we have determined, we find better agreement than has been obtained using quasiparticle-vibrational models.

We have recently constructed a model for exotic decay studies using a cubic potential for the overlapping region that is smoothly connected by a Yukawa-plus-exponential potential for the region after separation. In this model, the zero-point vibration energy is explicitly used without violating the energy conservation and the inertial mass coefficient is made dependent on the center of mass distance, but the deformation effect has not been included. In this work, it is taken into account in both the parent and the daughter nuclei, keeping the emitted nucleus always spherical. This model is applied to the cases of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ emissions and also for the recently reported cases of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{28,30}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{34}{}_{}{}^{}\mathrm{Si}$ emissions. It is found that the effect of the fragment deformation (which is always very small in the above decays) on lifetime is negligible while the parent deformation plays an appreciable role in the lifetime calculations.

We have studied the nucleus ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$ within a multichannel resonating group calculation based on many-body p+α and d${+}^3$He configurations and pseudostates as well as on effective nucleon-nucleon interactions containing central, spin-orbit, and tensor components. The known levels in ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$, identified by the p+α phase shifts and the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(d,p${)}^4$He fusion cross section, can consistently be described by our approach. Special distortion effects in the sense of Tang and collaborators are discussed for these states.

A general result for the eigenenergies of the one-dimensional Dirac equation for an arbitrary array of delta-function potentials of either Lorentz scalar or vector type is developed. This result is then used to discuss a finite one-dimensional model of the nucleus from which the energy bands of the constituent quarks may be obtained. The resulting energy eigenvalues are compared with those obtained previously via a similar model based on a Klein-Gordon equation. In contrast to this alternative treatment a system consisting of massless quarks confined to a regular periodic one-dimensional nucleus is found to be unbound. In the near ultra-relativistic limit binding to first order in the mass is found, thus conforming unexpectedly with the nonrelativistic limit. The possible surface states are examined and it is found that the so-called Dirac surface states are not expected for potentials of either Lorentz character. The existence and effect of quark surface states is also discussed in terms of our nuclear model. Finally the scattering coefficients for a relativistic particle in an arbitrary array of delta-function potentials are determined and their implications with regard to quark tunneling in nuclei are discussed.

The implication of invariance under local gauge transformation is investigated for electromagnetic interactions of nucleons and pions, which are particles extended in space time. It is shown that it is possible to derive electromagnetic interactions that are nonlocal and at the same time maintain local gauge invariance. Unlike the line current distribution assumed in the literature, the obtained current has a more flexible form that allows phenomenological analyses. It is proven that the current operators satisfy Ward-Takahashi equations for the nucleon, pion, and pion-nucleon vertex.

High-spin states of isotonic ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ and ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ were studied by means of the ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$${(}^{40}$Ca, α3pnγ${)}^{96}$Rh and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$${(}^{40}$Ca, α2pnγ${)}^{97}$Pd reactions, respectively, with ${\mathit{E}}_{\mathit{l}\mathit{a}\mathit{b}}$=167 MeV. Levels up to 5.5 MeV with ${\mathit{J}}^{\mathrm{\pi }}$=${15}^{+}$ in ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ were populated while levels in ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ up to 7.5 MeV were found. The yrast (21/$2^{+}$ level of ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ was found to decay to a (19/$2^{+}$ level, in contrast to the behavior of the lighter odd-A isotones. An attempt to measure lifetimes using a neutron-γ coincidence technique revealed no new isomers in either nuclide with ${\mathit{t}}_{1/2}$≥5 ns. The discovery of two low-lying transitions of 125 keV in ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ requires a slight revision of a recently reported value of its atomic mass as well as that of isobaric ${}_{}{}^{96}{}_{}{}^{}\mathrm{Pd}$. The high-spin structure and the N=51 systematics, particularly the location of the ν${\mathit{g}}_{7/2}$ strength, are compared with the results of shell-model calculations.

We demonstrate that, within the relativistic σ-ω model, the uniform mean-field solution for infinite nuclear matter is unstable for certain values of the scalar mass. For scalar masses greater than about 690 MeV, there is a state of nuclear matter which has a spatially periodic density and is lower in energy than the uniform state. We also demonstrate that the periodic state of nuclear matter has a lower compressibility than the uniform state, and that the density of the periodic state can be interpreted in terms of alpha-particle clustering. Furthermore, the secondary effects of the instability of nuclear matter can be seen in relativistic calculations of finite nuclei and similar effects are present in electron scattering data.

The rotational vibrations (${\mathit{K}}^{\mathrm{\pi }}$=$1^{+}$ states) in 16 even-even Xe, Ba, and Ce nuclei are studied in the quasiparticle random-phase approximation with a mean field given by a deformed Woods-Saxon potential and residual forces: a self-consistent quadrupole-quadrupole interaction, a spin-spin interaction, and a force that restores the rotational invariance of the Hamiltonian. A shell effect is found which is typical for this mass region: a strong orbital character of almost all low-energy (2.5–5 MeV) excitations, while the higher-energy ones are predominantly spin flip. The comparison of random-phase approximation M1 transition densities and (e,e’) form factors with the microscopic realization of the two-rotor model $1^{+}$ state allow us to conclude that the strongly orbital low-energy random-phase approximation states perform the scissor-type motion described by the two-rotor model, but only few particles are involved in this motion.

A method for obtaining collective Hamiltonians in linked diagram expansions is given. Effects of the Pauli principle have been properly taken into account. An illustration with a two-level pairing force model is given. The derivation of the interacting boson model and truncated quadrupole phonon model Hamiltonians as well as a comparison with the random-phase approximation are discussed.

High-spin states were excited in ${}_{}{}^{76}{}_{}{}^{}\mathrm{Br}$ via the reaction ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$${(}^{16}$t/rO,n2p) at a beam energy of 69 MeV. Several new high-spin states were found, including four levels in a previously unreported rotational band. A previously predicted signature inversion is confirmed.

The level structure of ${}_{}{}^{143}{}_{}{}^{}\mathrm{Nd}$ has been studied via the ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$${(}^{18}$O,5n) reaction. A level spectrum up to 5.3 MeV in excitation energy has been constructed from γ-γ coincidence spectra and γ-ray angular distributions. In addition to the single particle 1.228 MeV (13/$2^{+}$ state, others states arising from three- and five-quasiparticle configurations are identified, and spins and parities are suggested for these states.

The prompt gamma-rays from thermal nuteron capture in ${}_{}{}^{28,29,30}{}_{}{}^{}\mathrm{Si}$ have been studied and the radiative capture cross sections determined as 207±4, 120±3 and 107±2 mb, respectively. There has been a marked increase in the number of transitions observed in ${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$ and a complete decay scheme for this nucleus is presented. Two primary E2 transitions in ${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$ have been observed and their partial cross sections are compared with the prediction of the direct capture formalism. The measured neutron separation energies are ${\mathit{S}}_{\mathit{n}}$${(}^{29}$Si)=8473.61±0.04 keV, ${\mathit{S}}_{\mathit{n}}$${(}^{30}$Si)=10 609.21±0.04 keV, and ${\mathit{S}}_{\mathit{n}}$${(}^{31}$Si)=6587.32±0.20 keV.

The atomic mass excesses of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{88}{}_{}{}^{}\mathrm{Mo}$ were determined to be -77.807±0.031 and -72.703±0.021 MeV from the measured Q values of -40.136±0.030 and -43.278±0.020 MeV for the ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$(α${,}^8$He${)}^{86}$Zr(g.s.) and ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$(α${,}^8$He${)}^{88}$Mo(g.s.) reactions. The results were compared with some predicted values.

High quality analyzing power data (Δ${\mathit{A}}_{\mathit{y}}$≤0.05) for 800 MeV ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(p→,p’) scattering to the $0^{+}$ ground state and to the $3^{\mathrm{-}}$ 2.61 MeV collective state were obtained for θ /${\mathrm{r}}_{\mathit{c}.\mathit{m}.}$=22° to 37°, extending the range of momentum transfer out to 4.7 ${\mathrm{fm}}^{\mathrm{-}1}$. Theoretical predictions for these data were obtained using analyses based on both a nonrelativistic impulse approximation approach and a relativistic impulse approximation approach. For both the elastic and inelastic analyzing powers, the relativistic impulse approximation approach provided a better description at these large momentum transfers.

The levels up to 1.341 MeV in ${}_{}{}^{121}{}_{}{}^{}\mathrm{Te}$ and up to 1.037 MeV in ${}_{}{}^{123}{}_{}{}^{}\mathrm{Te}$ were excited via the ${}_{}{}^{121,123}{}_{}{}^{}\mathrm{Sb}$(p,n,γ) reaction. For the first time, lifetimes of the energy levels at 758, 807, 811, 912, 944, 1149, and 1341 keV in ${}_{}{}^{121}{}_{}{}^{}\mathrm{Te}$ and 784, 895, and 1037 keV in ${}_{}{}^{123}{}_{}{}^{}\mathrm{Te}$ have been measured using the Doppler shift attenuation technique. For the 831 keV level in ${}_{}{}^{121}{}_{}{}^{}\mathrm{Te}$ we have given a lower limit to the lifetime.

The moving source model parametrization has been used to explain satisfactorily the continuum background lying under the giant resonances excited through the inelastic scattering of 270 MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ from the targets with A values lying between 58 and 208.

Supersymmetric quantum mechanics provides a simple way to understand the scattering of a particle from a potential that contains a bound state that is Pauli blocked to the projectile. The singularity of the resulting potential found empirically in studies of nucleon-alpha scattering emerges naturally in supersymmetric quantum mechanics as does a direct and unique way to calculate the complete potential.

We compare the results of two sophisticated Monte Carlo simulators with published data on relativistic heavy-ion collisions. In addition, we include results of a simple Monte Carlo simulator, which is based on the gross features of the data and contains no correlations. We find that the data show a strong signal of intermittency that the three Monte Carlo simulators fail to reproduce. Furthermore, we find that the sophisticated simulators do no better than the simple one in that neither show any signal of intermittency at all.