By carrying out calculations on ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(e,e’p) reactions at different electron beam energies for fixed knocked-out proton kinematics, we examined whether, even in the presence of Coulomb distortions of the electron waves, the (e,e’p) cross section can still be separated into a reduced cross section ${\mathrm{\sigma }}_{\mathrm{red}}$(${\mathit{p}}_{\mathit{m})}$ and the e-p off-shell cross section. We found that if one uses an effective momentum approximation in calculating the e-p off-shell cross section, one gets a reduced cross section which is independent of the electron kinematics within a few percent.

It is shown that the nuclear effects playing a relevant role in deep inelastic scattering of polarized electrons by polarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are mainly those arising from the effective proton and neutron polarizations generated by the S’ and D waves in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. A simple and reliable equation relating the neutron ${\mathit{g}}_1^{\mathit{n}}$, and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${\mathit{g}}_1^3$, spin structure functions is proposed. It is shown that the measurment of the first moment of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ structure function can provide a significant check of the Bjorken sum rule.

The quasipotential formalism for elastic scattering from relativistic bound states is formulated based on the instant constraint in the Breit frame. The quasipotential electromagnetic current is derived from Mandelstam’s five-point kernel and obeys a two-body Ward identity. Breit-frame wave functions are obtained directly by solving integral equations with nonzero total three-momentum, thus accomplishing a dynamical boost. Calculations of electron-deuteron elastic form factors illustrate the importance of the dynamical boost versus kinematic boosts of the rest frame wave functions.

The α-decay properties of ${}_{}{}^{155}{}_{}{}^{}\mathrm{Lu}$ and ${}_{}{}^{157}{}_{}{}^{}\mathrm{Lu}$ show that their ground states are not π${\mathit{h}}_{11/2}$ (as they are in ${}_{}{}^{153,155}{}_{}{}^{}\mathrm{Tm}$, and ${}_{}{}^{151,153}{}_{}{}^{}\mathrm{Ho}$) but either π${\mathit{d}}_{3/2}$ or ${\mathrm{\pi }}_{1/2}$. From single-particle level systematics the π${\mathit{d}}_{3/2}$ assignment is favored. Calculations using the shell correction method predict the one-quasiparticle proton states based on the ${\mathit{h}}_{11/2}$, ${\mathit{d}}_{3/2}$, and ${\mathit{s}}_{1/2}$ subshells to appear very close in energy in Lu, Ta, and Re nuclei with N∼84, independently of equilibrium deformation.

We derive nonstrange baryon-baryon scattering amplitudes in the nonrelativistic quark model using the ‘‘quark Born diagram’’ formalism. This approach describes the scattering as a single interaction, here the one-gluon-exchange (OGE) spin-spin term followed by constituent interchange, with external nonrelativistic baryon wave functions attached to the scattering diagrams to incorporate higher-twist wave-function effects. The short-range repulsive core in the NN interaction has previously been attributed to this spin-spin interaction in the literature; we find that these perturbative constituent-interchange diagrams do indeed predict repulsive interactions in all I,S channels of the nucleon-nucleon system, and we compare our results for the equivalent short-range potentials to the core potentials found by other authors using nonperturbative methods. We also apply our perturbative techniques to the NΔ and ΔΔ systems: Some ΔΔ channels are found to have attractive core potentials and may accommodate ‘‘molecular’’ bound states near threshold. Finally we use our Born formalism to calculate the NN differential cross section, which we compare with experimental results for unpolarized proton-proton elastic scattering. We find that several familiar features of the experimental differential cross section are reproduced by our Born-order result.

Neutron transmission measurements have been carried out on a small sample (205.9 mg) of ${\mathrm{CaCO}}_3$ with a ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ enrichment of 49.1%. The parameters (spins and neutron widths) of eight resonances below the neutron energy of 20 keV have been determined. This information was combined with a previously measured thermal-neutron coherent scattering length to deduce the separate scattering lengths for the two spin states present in s-wave scattering. These values were used to calculate the direct (potential + valence) capture cross sections of the primary electric-dipole gamma transitions in ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ using optical-model potentials with physically realistic parameters. For those states below 6.2 MeV for which the l=1 (d,p) spectroscopic factors are known, the experimental cross sections are consistent with our current understanding of the direct and compound-nuclear capture processes. The processes leading to states above 6.2 MeV require further experimental and theoretical studies.

The g factor of the first excited, 3/$2^{+}$, 93.6 keV level of ${}_{}{}^{91}{}_{}{}^{}\mathrm{Sr}$ was measured using a beam of separated fission products and the time-differential perturbed angular correlation method. The result, g(3/$2^{+}$)=-0.231(11), is discussed in the context of the systematics of g factors of N=53–57 isotones, and found to be in good agreement with the prediction of the core-excitation model.

High spin excited states in neutron-rich nuclei ${}_{}{}^{112,114,116}{}_{}{}^{}\mathrm{Pd}$ have been investigated by measuring prompt γ rays emitted from a ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ spontaneous fission source. Two different measurements were performed. First, γ-γ coincidence data, necessary to determine the decay schemes, were obtained by using an array of 20 Compton-suppressed Ge detectors. Second, Z identification and the enhancement of a desired neutron channel were carried out using a x-n-γ multiplicity spectrometer. Ground state bands have been extended to ${\mathit{J}}^{\mathrm{\pi }}$=${10}^{+}$ for ${}_{}{}^{112}{}_{}{}^{}\mathrm{Pd}$, and ${\mathit{J}}^{\mathrm{\pi }}$=${12}^{+}$ for ${}_{}{}^{114}{}_{}{}^{}\mathrm{Pd}$ and ${}_{}{}^{116}{}_{}{}^{}\mathrm{Pd}$. Band crossings were observed in all three isotopes. It was found from cranked shell model calculations that these backbends are due to the alignment of two ${\mathit{g}}_{9/2}$ protons. The measured energy levels were also compared with predictions of the interacting boson model.

The two-neutrino double β decay matrix elements of ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$, ${}_{}{}^{106}{}_{}{}^{}\mathrm{Cd}$, and ${}_{}{}^{136}{}_{}{}^{}\mathrm{Ce}$ are calculated in the framework of the quasiparticle random phase approximation and the corresponding double ${\mathrm{\beta }}^{+}$/electron-capture (EC) decay (${\mathrm{\beta }}^{+}$${\mathrm{\beta }}^{+}$/${\mathrm{\beta }}^{+}$EC/ECEC) half-lives are estimated. The calculated ground-state-to-ground-state half-lives range from 3.9×${10}^{23}$ to 6.4×${10}^{19}$ yr indicating that the double ${\mathrm{\beta }}^{+}$/EC decay could, in principle, be detected using currently known experimental techniques.

Using an average one-body potential of Woods-Saxon type and using the experimental occupation probabilities to incorporate correlations the parabolic variation of charge radii of even isotopes of Ca (A=40–48) has been reproduced. The parameters of the potential were optimized by reproducing the zeroth-order shell model states of ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$. The details of the charge distribution has been evaluated by Fourier-Bessel analysis. The calculated values of rms radii are found to be in excellent agreement with the experiment.

g-matrix calculations have been performed for ${}_{\mathrm{\Lambda }}{}^5{}_{}{}^{}\mathrm{He}$, ${}_{\mathrm{\Lambda }}{}^{17}{}_{}{}^{}\mathrm{O}$, and ${}_{\mathrm{\Lambda }}{}^{41}{}_{}{}^{}\mathrm{Ca}$ by solving the Λ-Σ coupled channels Bethe-Goldstone equation. The potentials employed were the Nijmegen model D and Nijmegen soft core. Calculations were performed with various choices for the Pauli-forbidden space and the energy denominator. The Nijmegen model D does a reasonable job of reproducing most experimental single-particle energies, but the calculated ground-state binding energies vary smoothly from being underbound in the ${}_{\mathrm{\Lambda }}{}^5{}_{}{}^{}\mathrm{He}$ to overbound in ${}_{\mathrm{\Lambda }}{}^{41}{}_{}{}^{}\mathrm{Ca}$. The Nijmegen soft core underbinds all single Λ states, but gives level spacings which agree with experimental values.

Heavy fragment emission from a ${}_{44}{}^{100}{}_{}{}^{}\mathrm{Ru}$ compound nucleus at 400 and 800 MeV of excitation is analyzed to study the influence of level density models on final yields. An approach is used in which only quasibound shell-model levels are included in calculating level densities. We also test the traditional Fermi gas model for which there is no upper energy limit to the single particle levels. We compare the influence of these two level density models in evaporation calculations of primary fragment excitations, kinetic energies and yields, and on final product yields.

For a complex q-deformation parameter, the analytical energy expression of ${\mathrm{SO}}_{\mathit{q}}$(6) symmetry is shown to give all the three limiting symmetries of the U(6) group as well as all the intermediate results of mixed symmetries; i.e., it works equivalently as the numerically solvable general Hamiltonian of the s, d interacting boson model (IBM). Also, a symmetry triangle, equivalent to Casten’s symbolic symmetry triangle for the IBM, is obtained. The q-deformation parameter is found to behave as the symmetry mixing parameter, similar to one in the IBM. Applications are made to a range of nuclei, covering all the possible cases.

The equation of state of the baryonic matter containing nucleons and delta particles using the derivative scalar coupling model is studied. Comparison of the results with those obtained in a nonlinear σ-ω model yields the same equilibrium value of the effective mass and the compressibility constant.

We determine the phenomenological cluster-cluster interactions of the algebraic model corresponding to the most often used effective two-nucleon forces for the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+α system.

We report some results for light nuclei that strongly suggest that it is possible to construct good nuclear single-particle wave functions on the basis of recently available, shell related experimental information, by recourse to an information theory based inference approach.

With the ALADIN forward spectrometer the fragmentation of gold nuclei at 600 MeV per nucleon after interaction with carbon, aluminum, copper, and lead targets has been investigated. The results are compared to quantum-molecular-dynamics (QMD) calculations using soft and hard equations of state as well as a soft equation of state with momentum-dependent forces. Whereas the QMD has been successfully applied to heavy ion collisions at lower energies, it is not possible to reproduce the fragment distributions and the light-particle multiplicities observed in this experiment at relativistic energies. To study the reasons for the discrepancy between the experimental data and the simulations we investigated the time evolution of the nuclear system after a collision and the disintegration pattern of excited nuclei in the QMD approach.

Azimuthal angle correlations have been measured for Li-Li pairs from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ + ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ag}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ (17A, 27A, and 34A MeV). Many of these correlations exhibit enhancements at Δcphi of 0° and 180°, the classical pattern for evaporation from a hot, high-spin source. A very different pattern is predicted by a simple multifragmentation model, i.e., a peak at Δcphi≊60°. This peak is driven by the rapid Coulomb explosion of a nonrotating nucleus. The latter pattern is not observed experimentally, however, if collective rotation is included in the multifragmentation model, its predictions are more consistent with the observations. Such comparisons can give a promising test for sequential emission from a rotating source versus instantaneous explosive multifragmentation, but one needs a very good selection of collision centrality to reduce the role of the collective rotation. For most of these data the dominant driving forces seem to be rotational motion perturbed by final-state Coulomb repulsions for time delays of the order of ${10}^{\mathrm{-}22}$ s between successive emissions of Li fragments.

Cross sections for the production of the target fragments in the interaction of ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ with 47 MeV/nucleon ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ions have been measured with off-line γ spectroscopy. The mass yield distributions were deduced assuming a Gaussian charge distribution function. The results were compared with statistical fusion-fragmentation model calculations.

The spatial correlation among the four He ions coming from the disassembly of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectile on ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ targets has been studied at 94 MeV/nucleon. Charged particles have been detected by a multielement array of plastic scintillators covering the angular domain between 3° and 150°. Standard relativistic kinematics has been used to reconstruct the excitation energy of the primary projectilelike nucleus (${\mathit{E}}_{\mathrm{PLN}}^{\mathrm{*}}$). Mean values of this quantity are found independent of the target mass and the comparison with existing similar data taken at lower bombarding energies shows a saturation of ${\mathit{E}}_{\mathrm{PLN}}^{\mathrm{*}}$ around 3 MeV/nucleon. An event-by-event analysis has been performed in order to study the distributions of some global variables such as coplanarity, sphericity, and relative angle, helpful in the understanding of the topological characteristics of the process and in the evaluation of its time scale. Experimental data have also been compared with the results of Monte Carlo simulations based on different reaction mechanisms and it is possible to conclude that sequential emission of the fragments is preferred.