Angular distributions for the elastic and inelastic alpha scattering from ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at ${\mathit{E}}_{\mathrm{\alpha }}$=40 and 45 MeV are analyzed in the framework of microscopic folding model. Transition densities are calculated from improved s-d shell-model wave functions and are also compared with those extracted from inelastic electron scattering data. The density-dependent Jeukenne-Lejeune-Mahaux interaction is used, besides the M3Y interaction, in an attempt to fit the large-angle data. Fairly good agreement with the data is obtained. The extracted ${\mathit{M}}_{\mathit{n}}$/${\mathit{M}}_{\mathit{p}}$ value for the $2^{+}$ excited state of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ also compares well with the shell-model prediction.

The elastic scattering of weakly bound projectiles such as deuteron and ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ nucleus are examined including the break-up process to the continuum excited states. The eikonal approximation is employed to derive the optical potential which includes the dynamical polarization potential due to the break-up process. The dynamical polarization potential is realized to be closely related to the fluctuation of the constituents of the projectile nucleus in its ground state. Strong effect of the break-up process on the ${}_{}{}^{11}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C optical potential is found, which is qualitatively similar to those known for the deuteron optical potential. The elastic scattering differential cross section for ${}_{}{}^{11}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C is calculated with the obtained optical potential. It is found that the scattering cross section decreases rapidly for large scattering angle compared with the ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ elastic scattering.

Using the example of ${}_{}{}^{12}{}_{}{}^{}\mathrm{-}_{}^{208}{}_{}{}^{}$Pb elastic scattering at ${\mathit{E}}_{\mathrm{lab}}$=1449 MeV it is shown that, at sufficiently high energies, a full quantum mechanical inversion of heavy-ion scattering data can be performed. Furthermore it is pointed out that the strong absorption model as parametrized by McIntyre, Wang, and Becker is associated with a potential having strong repulsion at the origin. That repulsion is a remnant of the built-in point Coulomb S matrix. Finally, a systematic study is presented to define the necessary accuracy of experiment required to extend the knowledge of the nucleus-nucleus interaction to smaller radii.

We have made a precise measurement of the d-C total cross sections at 2.0, 2.4, 3.0, and 4.0 GeV/c, and the d-Al total cross sections at 2.0, 3.0, and 4.0 GeV/c. The data were obtained by means of the transmission method covering the momentum transfer squared range of 0.001 to 0.009 (GeV/c${)}^2$ at each momentum. Our results are in good agreement with the Glauber model.

A systematic set of measurements of the global transverse energy distributions, dσ/${\mathit{dE}}_{\mathit{T}}$ and ${\mathit{dE}}_{\mathit{T}}$/dη, from beams of protons, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at 14.6A GeV/c, incident on targets ranging from Be to Au is presented. The detector was a semicircular array of lead-glass blocks, covering polar angles 9°<θ<32°, whose total response provides a good measure of the produced particle yield in the central rapidity region of these reactions. Proton-nucleus spectra exhibit a similar shape on the high-energy tail, independent of target, suggesting that produced particles in such events arise mostly from the first collision of the projectile proton. For targets heavier than Cu, the high-energy edges of the oxygen-nucleus spectra, and of the silicon-nucleus spectra, reach ratios consistent with the geometry of central collisions. Angular distributions, ${\mathit{dE}}_{\mathit{T}}$/dη, are characterized by Gaussian fits, and an acceptance-independent form of the differential cross section is found, based on the maximum value of ${\mathit{dE}}_{\mathit{T}}$/dη. The projectile dependence of nucleus-nucleus spectra is studied in terms of two very different models: simple energy scaling and the wounded projectile nucleon model of p+A convolutions.

Fireball, firestreak, and hadronic string models are shown to overpredict recent central 15A GeV Si+Au E802 spectrometer data. Claims in the literature about full nuclear stopping in Si+Au reactions are therefore not supported by these data. In fact, fits to the spectrometer data indicate that up to half of the projectile nucleons may lose less than one unit of rapidity after traversing 5–10 fm of nuclear matter, implying an unexpected long stopping length of ∼20 fm. On the other hand, E810, E814, and preliminary E802 ${\mathit{dN}}_{\mathrm{ch}}$/dη data are more consistent with the expected degree of stopping.

We have calculated ground-state properties of hadronic matter in a mean-field approximation to a nontopological soliton model in one spatial dimension. The high-density phase of the model is a free Fermi gas of massless fermions. The low-density phase, on the other hand, is a soliton crystal characterized by spatial density oscillations. For certain values of the parameters there is an additional uniform phase in which the underlying chiral symmetry of the Lagrangian is broken and the fermion mass is dynamically generated. A stability analysis of this uniform phase via linear response theory revealed ground-state instabilities at low density and for strong coupling. These findings were consistent with the predictions obtained by solving the mean-field equations by direct matrix diagonalization. In the weak-coupling limit the soliton crystal is characterized by fermion clustering around regions of strongest attraction (shallow bags). The strong-coupling limit, on the other hand, is reminiscent of the soliton kink solution where fermions are excluded from sectors of strongest attraction and are, instead, concentrated in regions where they are effectively massless.

Vacuum polarization is studied in a model with neutral vector mesons and Dirac baryons. The lowest-order polarization is known to produce a ghost pole when it is summed to all orders in the vector meson propagator. It is also known that the infrared structure of the meson-baryon (NNω) vertex in this model produces a proper vertex function that is strongly damped at large spacelike momentum transfer; this is analogous to the result first derived by Sudakov in quantum electrodynamics. When the model vertex function is approximated by its on-shell form and combined with the lowest-order polarization, the vacuum contributions are significantly reduced. The resulting random-phase approximation meson propagator has no ghost pole and is finite at large spacelike momenta. Implications and perspectives of this result and necessary extensions of this calculation are also discussed.

The reaction ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$(p,γ${)}^{37}$K has been measured in the proton energy range of ${\mathit{E}}_{\mathit{p}}$=0.32–0.93 MeV. A new resonance was found at ${\mathit{E}}_{\mathit{R}}$=321 keV. We have measured the branching ratios and the resonance strength. The stellar reaction rates which are dominated by this resonance for temperatures T=0.07–0.9 GK are calculated. Network calculations have been performed to investigate the influence of the new stellar rates on the time evolution of the ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$ abundance during explosive H burning.

We investigate the breakup process in light heavy ion reactions. With the help of a separable approximation proposed in a previous paper and using closed forms for radial integrals, we obtain simple expressions for the breakup cross section. The theory is applied to the reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{28}$Si→α${+}^{12}$C${+}^{28}$Si, and the results are shown to agree with the experimental data.

Comparison of previously published data for the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(p→,p→’) reactions at ${\mathit{E}}_{\mathit{p}}$=319 MeV and ${\mathit{E}}_{\mathit{p}}$=800 MeV suggests that the spin-dipole resonance near ω=18 MeV is dominated by $1^{\mathrm{-}}$ transitions. The feature of the reaction at the two energies which allows this ${\mathit{J}}^{\mathrm{\pi }}$ inference is that the transverse isovector nucleon-nucleon t-matrix amplitude ${\mathit{F}}_1$ is much smaller at 800 than at 319 MeV.

Excitation functions were measured for the ${}_{}{}^{49,50}{}_{}{}^{}\mathrm{Ti}$(n,p${)}^{49,50}$Sc reactions from threshold to 10.5 MeV. Use was made of the activation technique in combination with high-resolution γ-ray spectroscopy and anticoincidence ${\mathrm{\beta }}^{\mathrm{-}}$ counting. Nuclear model calculations using a computer code were performed for (n,p) reactions on ${}_{}{}^{46,47,48,49,50}{}_{}{}^{}\mathrm{Ti}$. The experimental excitation functions are reproduced well by the calculation involving a fixed set of global parameters and only one variable parameter (‘‘pairing shift’’) to take account of the odd-even and nuclear structure effects in the target nuclei.

An exhaustive survey of the presently available experimental data on allowed beta decays with logft≤6.0 for A≥228 nuclei results in identification of 30 transitions which are seen to obey the extended asymptotic quantum numbers selection rule ΔN=0, Δ${\mathit{n}}_3$+ΔΛ=0, ‖Δ${\mathit{n}}_3$‖≤2. All these transitions are seen to connect an up-spin (Σ=↑) proton in an N=${\mathit{n}}_3$+Λ=6 Nilsson orbital and a down-spin (Σ=↓) neutron, also in an N=${\mathit{n}}_3$+Λ=6 orbital. Two possible candidates for allowed unhindered decays are presented. Our analysis also reveals the first evidence for four-quasiparticle excitations in even-even nuclei of the actinide region.

We investigate the possibility of constructing a covariant phenomenology of high-spin particles based on the work of Weinberg. We put forth a simple algebraic method for investigating the dispersion relations E=E(p,m) satisfied by the solutions to the free-particle Weinberg equations. We find that these equations support solutions which do not satisfy ${\mathit{E}}^2$=± √${\mathbf{p}}^2$+${\mathit{m}}^2$. This motivates a proposal to build the phenomenology without explicit reference to a wave equation. We demonstrate the practicality of this approach by providing techniques for constructing the covariant spinors, free-particle field operators, and propagators which could then be used to construct a covariant perturbation theory.

An empirical model is proposed for three-quasiparticle states (3qp) which is based on the experimental data of one- and two-quasiparticle states in neighboring nuclei. Calculations have been performed for 3qp states in ${}_{}{}^{163}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{175}{}_{}{}^{}\mathrm{Lu}$, and ${}_{}{}^{177}{}_{}{}^{}\mathrm{Lu}$ to check the validity of the model. The ordering of the levels in a given 3qp quadruplet is correctly reproduced in all nuclei. Two strong rules are proposed for (nnp) or (ppn) configurations according to which the highest-lying member of a given quadruplet always has a spin combination in which the spins of like particles are parallel while those of unlike particles are antiparallel and the state having all three spins in the same direction cannot lie lowest in energy. For (nnn) or (ppp) configurations, however, the state having all three spins in the same direction will be the highest in energy.

Partial transitions between initial and final states of definite relative angular momentum are studied for the nonmesonic weak decay of ${}_{\mathrm{\Lambda }}{}^{12}{}_{}{}^{}\mathrm{C}$. Compact expressions for the matrix elements in momentum space are given for nucleons in any orbital. It is shown that, in contrast to nuclear matter, the S→S and S→P transitions contribute significantly to the total rate. Implications are discussed for the ratio of the neutron- to proton-induced rates and of the parity-violating to parity-conserving transitions. Furthermore, transitions coming from initial relative ΛN P states are shown to be small.

We study the effect of the inelasticity in the charge symmetric amplitudes on calculations of the charge symmetry breaking spin observable ΔA=${\mathit{A}}_{\mathit{n}}$-${\mathit{A}}_{\mathit{p}}$ in np scattering. The effect is significant (≳10%) above the Δ excitation threshold, but is vanishingly small below.

Significant discrepancies between theory and experiment have previously been noted for double neutron removal via electromagnetic processes in relativistic nucleus-nucleus collisions. The present work examines the cause of these discrepancies and systematically investigates whether the problem might be due to electromagnetic theory, nuclear contributions, or an underestimate of experimental error. Using cross-section systematics from other reactions it is found that the discrepancies can be resolved in a plausible manner.

We examine the dynamical effects in the canonical ensemble calculation of the specific heat of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ with and without interactions in the s-d shell. Allowing for the inclusion of a continuum as well as a discrete spectrum in both cases, it is seen that the peak in the specific heat is a consequence of the interaction and not a finite size effect. The same behavior is also observed in other systems.

We derive a general expression for the representation matrix elements for a vibrator and a displaced harmonic oscillator in an arbitrary number of dimensions. These matrix elements arise naturally in an eikonal treatment of scattering from complex systems and contain the results derived for proton-nucleus and electron-molecule scattering as special cases.