We present results for summed orbital $1^{+}$ strengths in Sm and Nd isotopes obtained from deformed Hartree-Fock+BCS calculations, using a microscopic formulation of the scissors mode (the PHFB model) that excludes spurious contributions. It is found that the calculated $1^{+}$ strengths for the two chains of isotopes are proportional to ${\mathrm{\delta }}^2$ and that the summed strengths up to 4 MeV are in fair agreement with experimental data. It is also found that when pairing is neglected the total scissors mode strength is proportional to δ rather than to ${\mathrm{\delta }}^2$. Analytical expressions are given for the explicit dependence on the deformation parameter with and without pairing, valid for the anisotropic harmonic oscillator model.

The spin-correlation coefficients in pp bremsstrahlung are calculated in order to investigate their sensitivity to off-shell effects of the nucleon-nucleon interaction. Overall, in the coplanar geometry, we find that these coefficients are very sensitive to off-shell effects. This holds even at proton scattering angles as large as ${\mathrm{\theta }}_1$=${\mathrm{\theta }}_2$=20°, where the analyzing power is weakly sensitive to these effects, the measurements are less difficult, and the interpretation of the data is more transparent than at smaller proton scattering angles.

The NNπ coupling constants are extracted in NN partial-wave analyses. The data base contains all pp and np scattering data below ${\mathit{T}}_{\mathrm{lab}}$=350 MeV. Introducing different coupling constants at the different NNπ vertices, at the pion pole we find for the pp${\mathrm{\pi }}^0$ coupling ${\mathit{f}}_{\mathit{p}}^2$=0.0751(6), for the nn${\mathrm{\pi }}^0$ coupling ${\mathit{f}}_{\mathit{n}}^2$=0.075(2), and for the charged-pion coupling ${\mathit{f}}_{\mathit{c}}^2$=0.0741(5). These results allow only small charge-independence-breaking effects in the NNπ coupling constants. If we assume charge independence, we find ${\mathit{f}}^2$=0.0749(4). The value found for ${\mathit{f}}_{\mathit{c}}^2$ is in agreement with the determination in a recent VPI&SU analysis of the πN scattering data, and with its determination in an analysis of the charge-exchange reaction p¯p→n¯n.

We calculated the two- and three-body enhancement factors ${\mathrm{\kappa }}_2$ and ${\mathrm{\kappa }}_3$ of the dipole sum rule of the triton, arising respectively from the two- and three-body interactions. We performed consistent calculations taking the same interactions for the triton wave function and for the sum rule. The magnitude of ${\mathrm{\kappa }}_2$ and ${\mathrm{\kappa }}_3$ are of the order of 0.80–0.86 and 0.03–0.04, respectively. The calculated integrated cross section and the bremsstrahlung weighted cross section are linearly correlated to the calculated triton binding energy.

The distribution of single-particle strength in nuclear matter is calculated for a realistic nucleon-nucleon interaction. The influence of the short-range repulsion and the tensor component of the nuclear force on the spectral functions is to move approximately 13% of the total strength for all single-particle states beyond 100 MeV into the particle domain. This result is related to the abundantly observed quenching phenomena in nuclei which include the reduction of spectroscopic factors observed in (e,e’p) reactions and the missing strength in low energy response functions.

It is shown that if the effects of nucleon binding on deep inelastic scattering are considered within many-body realistic descriptions of nuclei which include nucleon-nucleon correlations, the European-Muon-Collaboration effect in light and medium weight nuclei and nuclear matter can be accounted for in the region 0.2≤x≤0.5, but a systematic discrepancy between theory and experiment remains to be explained for 0.5≤x≤0.9.

A hybrid description of diffraction which combines a geometrical modeling of multiple scattering with many-channel effects resulting from intrinsic dynamics on the nuclear and subnuclear level is presented. The application to ${}_{}{}^4{}_{}{}^{}\mathrm{-}_{}^4{}_{}{}^{}$He elastic scattering is satisfactory. Our analysis suggests that, at large momentum transfers, the parton constituents of nucleons immersed in nuclei are deconfined.

The magnetic-dipole scissors mode in spherical to deformed Sm isotopes is studied in terms of the proton-neutron sdg interacting boson model, providing a good agreement with recent experiment by Ziegler et al. The present calculation correctly reproduces the increase of M1 excitation strength in going from spherical to deformed nuclei. It is suggested that there may be $1^{+}$ states which do not correspond to the scissors mode but absorb certain M1 strength from the ground state.

We present a self-consistent mean-field description of nuclear matter making use of light front dynamics and focus our attention on a model with nucleons coupled to scalar mesons. We derive the mean-field Dirac equation for nucleon separation energies. The nucleon-meson seagull interactions are included in the calculations. In the mean-field analysis, the nucleon momentum sum rule, which plays an important role in the description of deep-inelastic scattering from heavy nuclei, results from the thermodynamical consistency condition that there is no pressure at zero temperature. We obtain the same energy density of nuclear matter at rest as one derives in the instant form of dynamics. Our light front mean-field formalism describes nuclear matter in uniform motion at any possible velocity.

A shell-model calculation in the model space of the (0d,1s) and (0f,1p) major shells is made for the first-forbidden ${\mathrm{\beta }}^{\mathrm{-}}$ transition ${}_{}{}^{50}{}_{}{}^{}\mathrm{K}$($0^{\mathrm{-}}$)${\to }^{50}$Ca($0^{+}$). Various truncation schemes were evaluated and the one adopted was to allow at most two neutrons in the ν0${\mathit{f}}_{5/2}$ orbit. An evaluation of the ‘‘final-state’’ core-polarization effects is made perturbatively for the two rank-zero matrix elements which contribute to ΔJ=0 first-forbidden β decays. The core-polarization effect is also applicable to ΔJ=0 spin-dipole excitations in the A≊40 region. Comparison of the shell-model (impulse approximation) prediction to experiment indicates the need for an appreciable in-medium contribution to the timelike component of the weak axial current. The enhancement of 52% found in this comparison is in good agreement with the general trend of predictions for one-pion-exchange processes in ΔJ=0 first-forbidden decays in A=16 to 96 nuclei.

A projection operator in a collective boson space, which projects onto the physical subspace, is constructed. This makes it possible to identify spurious boson eigenstates by a simple prescription which does not refer to noncollective boson operators at any stage.

A new method based on a maximal-decoupling variational principle is proposed to treat the Pauli-principle constraints for calculations of nuclear collective motion in a truncated boson space. The viability of the method is demonstrated through an application to the multipole form of boson Hamiltonians for the single-j and nondegenerate multi-j pairing interactions. While these boson Hamiltonians are Hermitian and contain only one- and two-boson terms, they are also the worst case for truncated boson-space calculations because they are not amenable to any boson truncations at all. By using auxiliary Hamiltonians optimally determined by the maximal-decoupling variational principle, however, truncations in the boson space become feasible and even yield reasonably accurate results. The method proposed here may thus be useful for doing realistic calculations of nuclear collective motion as well as for obtaining a viable interacting-boson-model type of boson Hamiltonian from the shell model.

The production of intermediate-mass fragments ranging from Z=3 to 8 emitted in the reaction of 60 MeV alpha on an aluminum target has been experimentally studied. The energy spectra of the emitted fragments in the angular range of 20°–130° have been measured and the total production cross sections of each fragment have been estimated from the data. The double-differential cross-section data have been compared with the predictions made using (a) a phenomenological moving source model and (b) a binary fragmentation model. The absolute total emission cross sections for various fragments have been calculated assuming the statistical decay of a fully equilibrated compound nucleus and have been compared with the corresponding experimental estimates. It is found that the exit-channel deformation plays a significant role in the estimation of the Coulomb barrier of the separating nuclei. A theoretical procedure for the estimation of the exit-channel Coulomb barrier for the deformed system has been incorporated in the present calculation.

A stack containing plastic nuclear track detectors and Ag target foils was exposed to a ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ beam with an energy of 980 MeV/nucleon. The analysis was restricted to energies between beam energy and 200 MeV/nucleon. 2496 collisions with Ag target nuclei and 4114 with the lighter constituents H, C, and O of the detector material were analyzed in detail. For all interactions, projectile fragments with charge ${\mathit{Z}}_{\mathit{F}}$≥6 were measured and their emission angles were determined. This paper describes the experiment and presents charge yields and results about transverse momenta for events with different multiplicities. Details of multiplicity distributions, correlations between fragments and signatures related to multifragmentation as a critical process are discussed in a separate paper.

We analyze the largest set of fragment coincidence data at present available, that of the preceding paper. This set contains all projectile fragments 6≤Z≤65 produced in 6610 events of Au+Ag and Au+CR-39. We introduce a classification scheme based on the number of heavy fragments in order to define multifragmentation, spallation, and fission events. The multiplicity distribution P(${\mathit{m}}_{\mathit{Z}}$) is Poissonian, and the mean multiplicity as a function of Z can be described either by a power law or by an exponential. The slopes are independent of the projectile energy but depend on the target. While all investigated observables indicate that the multifragmentation in the case of a Ag target is a statistical process, we observe angular correlations in the case of the CR-39 target which indicate that probably the geometry and not the excitation energy is essential. Charge correlations are strong and only partially understood as yet. We find no positive sign for a liquid gas phase transition.

Scattering of 400 MeV polarized protons from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ to the $0^{\mathrm{-}}$;T=0 state at 10.957 MeV has been studied from 3° to 14° in the laboratory. Measured values of cross section and analyzing power are compared with relativistic and nonrelativistic calculations. It is found that interference from a two-step excitation through the $3^{\mathrm{-}}$ state at 6.130 MeV is required in order to reproduce the large negative values of analyzing power observed at low momentum transfer.

Angular distributions of the one- up to four-proton transfer have been measured in the system ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$${+}^{54}$Fe at an energy of ${\mathit{E}}_{\mathrm{lab}}$=291 MeV. The one- and two-proton-transfer angular distributions are well described by the distorted-wave Born approximation. The three- and four-proton transfers show strong deviations from this approach with contributions which are isotropic. The isotropic component is attributed to reaction processes with a longer time scale. This conjecture is supported by the observed total energy loss of 15–20 MeV, consistent with fission systematics, where strongly deformed and cold fragments are produced. These results are interpreted as the decay of a long-lived two-center system which is stabilized by shell effects.

The cross section of the ${}_{}{}^{103}{}_{}{}^{}\mathrm{Rh}$(γ,γ’${)}^{103}$${\mathrm{Rh}}^{\mathit{m}}$ reaction as a function of energy has been studied in the giant dipole resonance region. Natural rhodium was irradiated with bremsstrahlung of an electron beam on a platinum converter for electron energies of 14, 15, 17, 19, 20, and 30 MeV. Induced isomeric activities as a function of beam energy were measured with γ-ray spectrometry using a high-purity Ge detector. The integral cross section obtained from the yield curve was found to be uniformly 22.6±4.0 mb MeV for all of the beam energies. The experimental data have been compared with the predictions of a γ-ray cascade model calculation where competing open nucleon emission channels were considered and a spin-dependent preequilibrium correction was applied in addition to the equilibrium transition probabilities. The calculation provided one pronounced peak in the cross section–at the (γ,n) threshold–with an integral of 24.3 mb MeV. Neither the experiments nor the calculation confirmed the existence of a comparable second peak observed in earlier experiments.

We present a new type of flow analysis, based on a particle-pair correlation function, in which there is no need for an event-by-event determination of the reaction plane. Consequently, the need to correct for dispersion in an estimated reaction plane does not arise. Our method also offers the option to avoid any influence from particle misidentification. Using this method, streamer chamber data for collisions of Ar+KCl and Ar+${\mathrm{BaI}}_2$ at 1.2 GeV/nucleon are compared with predictions of a nuclear transport model.

A static analysis of measurements of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ elastic electron-scattering cross sections demonstrates unambiguously the existence of a form-factor energy dependence beyond that due to Coulomb distortion effects. This energy dependence increases smoothly as a function of momentum transfer and incident energy in the region covered by the experiments (1.0<${\mathit{q}}_{\mathrm{eff}}$<2.3 ${\mathrm{fm}}^{\mathrm{-}1}$, 240<${\mathit{E}}_0$<690 MeV). Outside the first diffraction minimum the discrepancies between the form factors deduced from data obtained at different energies are as large as 5%; in the minimum discrepancies as large as 18% have been observed. Including dispersion corrections which are reasonably compatible with this observed energy dependence in the analysis of the data increases the rms charge radius deduced for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ by 0.007 to 2.478(9), fm, which is in excellent agreement with the value from muonic x-ray studies.