We consider the effects of nonlocality on the determination of the deuteron radius for model potentials. We show that the relation between the model values for the radius and the scattering length which holds for local potentials is not necessarily valid for nonlocal potentials. It is possible for nonlocal potential models to produce a deuteron of smaller radius as required by experimental data. In particular, we show that the Reid model can be amended with the inclusion of an attractive separable term to produce a change in the radius which is of the correct order of magnitude.

We continue our studies of a covariant, solvable model of two scalar particles which are bound to form a ‘‘scalar deuteron.’’ We calculated the hadronic tensor for that system in a previous publication and performed a y-scaling analysis. In this work we show how the scaling function of the theory, F(${\mathit{Q}}^2$,y), may be expressed in terms of the momentum distribution of the target particles. We stress the importance of extracting the correct kinematic factors before defining the scaling function. (These kinematic factors take into account the fact that one is scattering from moving, off-shell particles.) We show that, only if the kinematic factors are extracted properly, will the momentum distribution obtained from the response function exhibit proper scaling behavior. That is, the extracted momentum distribution will approach the theoretical distribution in the scaling limit, if an optimum choice of kinematic factors is made.

The threshold electrodisintegration cross section and electromagnetic form factors of the deuteron are calculated by using the Argonne ${\mathit{v}}_{14}$ model for the nucleon-nucleon interaction to generate the bound- and scattering-state wave functions. The exchange-current operator is constructed to be consistent with the interaction model. The calculated electrodisintegration cross section is in good qualitative agreement with the experimental data over the whole measured momentum-transfer range, and is sensitive to the electromagnetic form factors of the nucleon. The calculated form factors appear to be in good agreement with the empirical values, although uncertainties in the isoscalar model-dependent exchange-current contributions and nucleon electromagnetic form factors prevent definite predictions to be made at high values of momentum transfer. Finally, the cross section for radiative capture of thermal neutrons on protons is found to be within less than 1% of the measured value.

We report a comprehensive analysis of the crossing related reactions p(γ,${\mathit{K}}^{+}$)Y and p(${\mathit{K}}^{\mathrm{-}}$,γ)Y for Y=Λ, ${\mathrm{\Sigma }}^0$, and Λ(1405). Our model, which incorporates both crossing and duality, reproduces all existing Λ and ${\mathrm{\Sigma }}^0$ cross-section, polarization, and capture branching-ratio data while providing useful constraints for the Λ(1405) magnetic transition moments. While the p(γ,${\mathit{K}}^{+}$)Λ(1405) cross section is predicted to be measurable at CEBAF (σ∼1 μb), parity conservation leads to a model-independent suppression of the p(γ,${\mathit{K}}^{+}$)Λ→(1405) polarization and p(${\mathit{K}}^{\mathrm{-}}$,γ)Λ(1405) cross section (σ∼1 nb).

An alignment of the nuclear spin has been observed for a secondary radioactive beam of ${}_{}{}^{14}{}_{}{}^{}\mathrm{B}$ produced in the fragmentation of a 60 MeV/nucleon ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ beam impinging onto a ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ target. The fragments were separated and analyzed in momentum by means of the doubly achromatic spectrometer LISE. The spin alignment was determined through a measurement of the anisotropy of the β-delayed γ-ray emission. The alignment is found to be small in the momentum region corresponding to the peak of the fragmentation yield, whereas it takes a large negative value for the high-momentum tail. This result is discussed in terms of a simple model of projectile fragmentation. The relevance of this result for the determination of nuclear moments far from stability is considered.

The probability of double K-shell vacancy production in the electron capture decay of ${}_{}{}^{139}{}_{}{}^{}\mathrm{Ce}$ to the 166-keV level of ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ has been investigated. Triple coincidences between the 166-keV gamma ray, the La satellite Kα x ray, and the La hypersatellite Kα x ray were measured using two intrinsic Ge detectors. We looked for the sum of two of the three radiations in one detector in coincidence with the third radiation in the other detector. The probability of double K-shell vacancy production per K-shell electron capture (${\mathit{P}}_{\mathit{K}\mathit{K}}$) was found to be (2.0±1.6)×${10}^{\mathrm{-}6}$. From this and the known ${\mathit{P}}_{\mathit{K}\mathit{K}}$ for ${}_{}{}^{131}{}_{}{}^{}\mathrm{Cs}$ we estimate a probability for zero K-shell vacancy production (shakedown) per K-shell electron capture of ≲2.4×${10}^{\mathrm{-}5}$ for ${}_{}{}^{139}{}_{}{}^{}\mathrm{Ce}$.

The high-spin states of ${}_{}{}^{74}{}_{}{}^{}\mathrm{Br}$ were studied via the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$${(}^{32}$S,αpn${)}^{74}$Br and the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{19}$F,2pn${)}^{74}$Br fusion-evaporation reactions at energies of 105 and 62 MeV, respectively, using the Florida State University Tandem LINAC. γ-γ coincidence arrays were produced using four Compton-suppressed Ge detectors. Two independent groups of γ rays were studied–one of positive parity and one of negative parity, both of which appear to be based on an isomeric $4^{\mathrm{}(+)\mathrm{}}$ state. Lifetimes were measured using both the Doppler-shift attenuation and recoil-distance methods. A cranking-model analysis of the bands shows that the kinematic and dynamic moments of inertia for the bands are rather similar and fairly constant for high spins with values of (20–23)${\mathrm{ħ}}^2$/MeV. A phase reversal occurs in the signature splitting in the yrast band around spin 9 which is related to the quasiparticle alignments. The lifetimes imply an average axial quadrupole deformation of 0.37 in the yrast band and 0.34 in the negative-parity band. These deformations are close to those predicted by Hartree-Fock-Bogolyubov cranking calculations.

Levels in ${}_{}{}^{190}{}_{}{}^{}\mathrm{Hg}$ were studied by radioactive decay of isotopically separated ${}_{}{}^{190}{}_{}{}^{}\mathrm{Tl}$. A new band was observed with spin parity (energy, keV) of $0^{+}$(1279), $2^{+}$(1571), $4^{+}$(1975), and $6^{+}$(2510). Electric monopole transitions were observed between this band and the ground-state band. Relative B(E2) values for intraband transitions in the new band were found to be ∼200 times those for interband transitions. Systematics of shape coexistence in the light Hg isotopes and their possible relevance to recent observations of superdeformation in these nuclei are discussed.

Measurement has been made of the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$(γ,pn+np) cross section. The cross section rises to a maximum of 1.2 mb at 27.5 MeV, approximately one-tenth of the total (γ,n) cross section there. The integrated cross section is correspondingly small (11.8 Mev mb to 43 MeV). As a result, the assignments of isospin distribution in the giant dipole resonance made by Woodworth et al. [Phys. Rev. C 19, 1667 (1979)] are unaffected by neglect of this reaction channel.

The neutron total cross section for ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ has been measured over the incident neutron energy range 0.007–50 MeV. R-matrix analysis of the cross section from 0.007 to 1.52 MeV provides resonance parameters which provide a complete description of the neutron scattering functions for the ${\mathit{s}}_{1/2}$, ${\mathit{p}}_{1/2}$, and ${\mathit{p}}_{3/2}$ scattering channels and less nearly complete scattering functions for the ${\mathit{d}}_{3/2}$ and ${\mathit{d}}_{5/2}$ channels. The back-shifted Fermi-gas model is used to model the level densities for s-, p-, and d-wave resonances.

The ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$(α,d${)}^{26}$Al reaction leading to the 0.23 MeV $0_1^{+}$, T=1 and the 3.16 MeV $2_2^{+}$, T=1 states were measured at ${\mathit{E}}_{\mathrm{\alpha }}$=64.7 MeV. Cross sections for these isospin-forbidden transitions were compared with exact-finite-range second-order distorted wave Born approximation (DWBA) calculations for successive-transfer processes (α${\mathrm{-}}^3$He-d) and (α-t-d). The DWBA calculation with spectroscopic amplitudes obtained from the full sd-shell model was found to underestimate the cross section for the $0^{+}$ state by a factor of 200, while a normalization factor of 10 was obtained for the $2^{+}$ state. About 5% isospin impurity in the $0^{+}$ state of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ was required to obtain the same normalization for the $0^{+}$ state.

The level mixing spectroscopy method has been applied to measure the static quadrupole moments of six isomeric states in ${}_{}{}^{213}{}_{}{}^{}\mathrm{Fr}$, ${}_{}{}^{212}{}_{}{}^{}\mathrm{Fr}$, and ${}_{}{}^{211}{}_{}{}^{}\mathrm{Fr}$ (Z=87). For isomers with the proton configuration π${\mathit{h}}_{9/2}^4$${\mathit{i}}_{13/2}$ a large increase of the quadrupole moment was observed with the removal of neutrons from the closed N=126 core: Q(29/$2^{+}$${,}^{213}$Fr)=-70(7) e ${\mathrm{fm}}^2$, Q(${15}^{\mathrm{-}}$${,}^{212}$Fr)=-80(12) e ${\mathrm{fm}}^2$, and Q(29/$2^{+}$${,}^{211}$Fr)=-107(18) e ${\mathrm{fm}}^2$. Quadrupole moments for very high spin states were also measured: Q(65/$2^{\mathrm{-}}$${,}^{213}$Fr)=-219(53) e ${\mathrm{fm}}^2$, Q(${27}^{\mathrm{-}}$${,}^{212}$Fr)=-152(31) e ${\mathrm{fm}}^2$, and Q(45/$2^{\mathrm{-}}$${,}^{211}$Fr) =-198(56) e ${\mathrm{fm}}^2$. The observed values are in good agreement with shell-model calculations, but are lower than that predicted using the deformed-independent particle model. The implantation behavior of Fr in a Tl host is also discussed.

The level scheme of ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ has been studied by combining the results of ${}_{}{}^{115}{}_{}{}^{}\mathrm{Sn}$(n,γ${)}^{116}$Sn and ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$(n,n’γ${)}^{116}$Sn experiments. Both experiments were performed using isotopically enriched samples and Ge γ-ray detectors. Based on the thresholds of γ-ray excitation functions measured for the ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$(n,n’γ) reaction and the precise γ-ray energies from the capture reaction, 100 levels were observed below 4.3 MeV excitation energy. Approximately half of these were not known previously. Forty-eight of these levels have unique or tentative spin-parity assignments, and for ten more the spin has been restricted to a single value. The spin-parity for most other levels below 4.3 MeV excitation has been restricted to a few values. These spin-parity assignments and limitations were derived mainly from (n,n’γ) angular distribution measurements, together with additional information obtained from the cross section magnitudes in both experiments.

Above 4.3 MeV excitation energy, 55 additional levels are proposed, based only on the ${}_{}{}^{115}{}_{}{}^{}\mathrm{Sn}$(n,γ) results. No ${\mathit{J}}^{\mathrm{\pi }}$ information is available for these higher-lying levels beyond the fact that they most probably all have J≤4. The level scheme below 4.3 MeV from the current work, together with known high-spin levels up to 5.4 MeV seen in other experiments, are compared to the combined predictions of the two-broken-pair model, the interacting boson model, and the deformed collective model. In addition, several states have been phenomenologically identified as proton 1p-1h and collective quadrupole-octupole two-phonon excitations. It is concluded from the good agreement between experiment and these models that all levels in ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ with J≤6 up to an excitation of 4.0 MeV and J≤3 up to 4.3 MeV may have been experimentally identified. The nearest-neighbor spacing distribution is intermediate between that of a Gaussian orthogonal ensemble and that of a Poisson distribution, with a slight preference for the former. The neutron separation energy was determined to be 9563.47±0.11 keV.

The B(E2)↑ values for the first $2^{+}$ state of even-even nuclei in the Z≥50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The B(E2)↑ values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical B(E2)↑ and B(E3)↑ systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying $2^{+}$ states below 2.3 MeV is found to be surprisingly constant in the 60<A<250 region except near closed shells.

A study is made of the influence of many-body corrections on the longitudinal response function for the inclusive quasielastic (e,e’) reaction. This response function is well known to be suppressed, by about a factor of 2, when compared with theoretical predictions based on the concept of single nucleon ejection. This is a characteristic of the data that persists through a wide range of different nuclei and suggests a violation of the Coulomb sum rule. It is shown here how an estimation of the effect of many-body correlations, at large momentum transfers, including a consistent treatment of inelastic final-state interactions, can be computed through a relationship to the nuclear optical model. The approximations are such that the Coulomb sum rule is guaranteed to remain satisfied providing the optical potential is Hermitian analytic. Calculations of the longitudinal response are carried out within the Fermi-gas model using phenomenological parametrizations of the nuclear optical potential. The reductions in both the peak strength and the total integrated response are signficant, but not sufficient to explain the discrepancy between theory and experiment. The resulting distribution of strength is characterized by the energy-weighted sum rule which remains satisfied to the level of the approximations, about 5%.

The interplay between nuclear rotation and the pairing correlations is studied in the single-j shell model space with j=13/2. For this study, we employ both the cranking model and the particle-rotor model, the Hamiltonians of which are exactly diagonalized to avoid the ambiguity of the number-nonconserving pair field approximation. The discussions on the merit of the two models show that the particle-rotor model is more reliable than the cranking model. Through the investigations of the spin alignments, the pairing energy gap, and the wave functions, it is shown that the pairing vibrational modes play very important roles. The processes of the collapse of nucleon pairs due to the nuclear rotation are also discussed.

Shell-model calculations are described for A=204–212 nuclei. These calculations use the Kuo-Herling realistic effective interactions for hole states and particle states relative to ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. These interactions contain a bare part and a core-polarization contribution. The contribution of the core polarization was varied to find the best fit to the energy spectra of A=204–206 and 210–212 nuclei. This and other modifications to the Kuo-Herling interaction—designed to give better agreement with experimental energy spectra—are discussed. Aspects of the spectroscopy of ${}_{}{}^{211\mathrm{-}212}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$, ${}_{}{}^{212}{}_{}{}^{}\mathrm{Ra}$, ${}_{}{}^{210}{}_{}{}^{}\mathrm{Bi}$, and ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$ are presented in order to illustrate the use of the Kuo-Herling particle interaction. Deficiencies in the Kuo-Herling interaction are described and the desirability and possibility of an improved calculation of the interaction is emphasized.

A method is shown to derive a consistent Hamiltonian of nucleon and meson system in a finite nucleus from a Lorentz-scalar Lagrangian. For this purpose, the Schwinger-Dyson method is applied to a many-body problem of the interacting nucleons and mesons in a finite system. Using this method, closed equations of exact Green’s functions for single-particle motions of a nucleon and a meson are derived. It is shown that the interactions of nucleons and mesons generate local dependent potentials in a finite system and that the potentials can be determined self-consistently on the basis of the many-body Schwinger-Dyson formalism. In the method, condensed meson fields are extracted from the meson fields and treated as c-number fields, so that the classical equations of the condensed fields become equivalent to those of the mean-field theory originally proposed by Walecka et al.$-— The present method is regarded as a natural extension of mean-field theory to a full quantum treatment for finite systems. The method provides a self-consistent description of the single-particle motions of nucleons and mesons and their mutual interactions. It allows us to include full quantum effects and to describe not only the ground state but also excited states in a systematic way.

The observed systematics of the low-lying states in ${}_{}{}^{98\mathrm{-}110}{}_{}{}^{}\mathrm{Cd}$ nuclei and the high-spin yrast spectra with ${\mathit{J}}_{\max }^{\mathrm{\pi }}$≤${14}^{+}$ are examined by carrying out Hartree-Fock-Bogoliubov calculations employing a pairing-plus-quadrupole-quadrupole effective interaction operating in a reasonably large valence space outside an inert ${}_{}{}^{80}{}_{}{}^{}\mathrm{Zr}$ core. Our calculations reveal that the systematics of the low-lying yrast states in ${}_{}{}^{98\mathrm{-}110}{}_{}{}^{}\mathrm{Cd}$ are intricately linked with the deformation producing tendency of the n-p interaction when operating between spin-orbit-partner (SOP) orbits. Our results indicate that such systematics depend crucially on the simultaneous increase of relative occupation probabilities of the (${\mathit{d}}_{5/2}$)-proton and (${\mathit{d}}_{3/2}$)-neutron orbits in the ${}_{}{}^{98\mathrm{-}100}{}_{}{}^{}\mathrm{Cd}$ isotopes.

The reaction ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$(n,p${)}^{15}$C was studied at a neutron energy of 288 MeV using the TRIUMF (n,p) charge-exchange facility and a high-pressure gas target. The angular distributions for spin dipole (ΔL=1) transitions to the states in ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}$ at energies 0 and 0.740 MeV, as well as for higher excitation energies, were measured and the results were compared with distorted-wave impulse approximation calculations. The measured distribution of the spin dipole strength agrees well with shell-model predictions, indicating that a rather simple model provides a satisfactory description of the ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ ground state, and of positive-parity states in ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}$ up to about 18 MeV excitation. The magnitude of the peak cross sections (at ≃7°) is described well by the calculations when the theoretical cross section is renormalized by a factor of 0.7. The calculated cross sections near 0° are generally smaller than experimental data. If this is a general feature of ΔL=1 transitions, it suggests that estimates of Gamow-Teller strength based on a multipole decomposition of measured cross sections may be too high.