Differential cross sections and analyzing powers were measured for ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$(d→,t${)}^{16}$O with polarized deuterons of 89 MeV. States of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ up to 22.89 MeV excitation energy have been studied with an overall resolution of 60 keV. Discrimination between analyzing powers (${\mathit{A}}_{\mathit{y}}$) for different j transfers was found to be very good. The unique ${\mathit{A}}_{\mathit{y}}$(θ) shapes were used to deduce ${\mathit{p}}_{1/2}$-${\mathit{p}}_{3/2}$ mixing ratios for those levels where it was significant. We find unexpectedly strong mixing for the 6.130 MeV, $3^{\mathrm{-}}$, and 8.872 MeV, $2^{\mathrm{-}}$, levels. Exact finite-range distorted-wave Born approximation calculations were used to identify l transfers and to extract spectroscopic strengths. Up to 23 MeV excitation, pickup strength is dominated by 1p transfer; less than 2% of the observed particle-hole strength results from 2s, 1d, or 1f transfer. Twelve particle-hole matrix elements for (${\mathit{p}}_{1/2}^{\mathrm{-}1}$${\mathit{d}}_{5/2}$) and (${\mathit{p}}_{3/2}^{\mathrm{-}1}$${\mathit{d}}_{5/2}$) configurations have been deduced. Comparison with previous work shows general agreement except for the T=0,${\mathit{J}}^{\mathrm{\pi }}$=$3^{\mathrm{-}}$ term.

Zero-degree cross sections have been measured for the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$(p,n${)}^{11}$C reaction at bombarding energies of ${\mathit{E}}_{\mathit{p}}$=160, 200, 494, 644, and 795 MeV. In addition, spectra have been obtained at laboratory scattering angles of 3° and 5° at 494 MeV, and the transverse spin-flip probability at zero degrees has been measured for ${\mathit{E}}_{\mathit{p}}$=160 MeV. These data are used to obtain estimates of the Gamow-Teller transition strength to final states in ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ up to an excitation energy of ${\mathit{E}}_{\mathit{x}}$≃14 MeV. The uncertainty (1 standard deviation) in the extracted transition strengths is estimated to be in the range (2–8)%. Measured cross sections for the first four excited states in ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ have been compared to distorted-wave impulse approximation calculations. In this comparison, no evidence is found in the cross-section data for certain effects associated with knock-on exchange and noncentral interactions.

Near-barrier and sub-barrier fusion excitation functions have been measured for the ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$${+}^{58,60,62,64}$Ni systems using a recoil velocity spectrometer to identify evaporation residues. A considerable amount of enhancement was observed for all systems studied. The measured excitation functions for ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$${+}^{58,62,64}$Ni are not in agreement with published results for these systems. The data were analyzed in the context of a coupled-channels model which took into account either the dependence of the fusion cross section on the coupling to surface vibrational modes, or, alternatively, on the orientation of deformed colliding nuclei. Very good agreement was obtained with the experimental data under the assumption that ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$ exhibits a moderate oblate static deformation, while the light Ni isotopes are spherical vibrators. On the other hand, the data for ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$${+}^{64}$Ni favor a moderate static oblate deformation for ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$.

The first postulation of excited states in neutron-rich ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ is presented. We postulate the levels in ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ to be populated by high- and low-spin isomers of ${}_{}{}^{76}{}_{}{}^{}\mathrm{Cu}$ with half-lives of 0.57 s and 1.27 s, respectively. Of 12 γ rays attributed to ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ decay, 11 are placed in a level scheme for ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ with eight excited states up to 3 MeV. A shell-model calculation has been carried out to reproduce the systematics of the neutron-rich Zn isotopes up to A=76. The model space involves active protons in orbitals between Z=28 and 50 and neutrons in orbitals filling the subshell between N=38 and 50.

Semiclassical simulation of finite nuclei, readily available for nuclear collisions, is presented by employing the classical equation of motion approach in conjunction with a nuclear structure model, the isomorphic shell model, previously and independently published. Emphasis is put on good approximation of the main nuclear properties and their preservation during the evolution of the simulation for times much longer than a typical reaction time.

The effect of one- and two-body dissipation on the damping of giant quadrupole resonances is studied in a semiclassic approach solving a Vlasov equation with a collisional relaxation time. The latter is microscopically evaluated from the equilibration of a distorted momentum distribution in a kinetic approach. Important effects from energy and angle dependent nucleon-nucleon (NN) cross sections and from the time variation of Pauli blocking are stressed. Once these points are suitably treated, a good agreement with the experimental systematics is obtained from the use of a free NN cross section.

Bethe ansatz methods are used to obtain an exact expression for the energy density for a system consisting of the (1+1)-dimensional sine-Gordon model coupled to an external scalar source. This method exploits the equivalence between the sine-Gordon model and the massive Thirring model. These calculations allow one to test various loop-expansion approximations to the effective potential for the scalar. Such calculations are of relevance to fundamental issues regarding quantum hadrodynamics.

The phenomenon of shape coexistence, occurring frequently in the vicinity of nuclear subshell closures, is investigated within a schematic model with protons in two subshells and neutrons in a single shell. The results of this study shed some light on how one should model the phenomenon within the interacting-boson framework and relates to previous phenomenological studies. Our model employs an SO(8${)}_{\nu }$⊗SO(8${)}_{\mathrm{\pi }+}$⊗SO(8${)}_{\mathrm{\pi }\mathrm{-}}$ dynamic symmetry to ensure exact decoupling of an S-D-pair space, thus providing a tight conceptual link with the interacting-boson model. The model has a critical point, namely, below a certain number of valence neutrons the deformed configuration ceases to coexist. This is intriguingly reminiscent of the data.

The interacting boson model (IBM) is applied at finite temperature for evaluation of a collective enhancement factor in nuclear level densities in the form of a canonical partition function. The most crucial variable turns out to be the effective boson number, whose temperature dependence is studied in the frame of a Nilsson-Bardeen-Cooper-Schrieffer model. Numerical results are obtained in the three IBM limiting symmetries.

An extension of the interacting boson approximation model is proposed by allowing for two- and four-quasiparticle excitations out of the boson space. The formation of band patterns based on two- and four-quasiparticle states is investigated in the SU(3) limit of the model. For hole-type (particle-type) fermions coupled to the SU(3) prolate (oblate) core, it is shown that the algebraic K-representation basis, which is the analog of the strong-coupling basis of the geometrical model, provides an appropriate description of the low-lying two-quasiparticle bands. In the case of particle-type (hole-type) fermions coupled to the SU(3) prolate (oblate) core, a new algebraic decoupling basis is derived that is equivalent in the geometrical limit to Stephens’ rotation-aligned basis. Comparing the wave functions that are obtained by diagonalization of the model Hamiltonian to the decoupling basis, several low-lying two-quasiparticle bands are identified. The effects of an interaction that conserves only the total nucleon number, mixing states with different number of fermions, are investigated in both the strong-coupling and decoupling limits. All calculations are performed for an SU(3) boson core and the h11/2 fermion orbital.

A momentum-analyzed, isomeric, radioactive ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}_{}^{\mathit{m}}{}_{}{}^{}$ beam (${\mathit{E}}_{\mathit{x}}$=1.12 MeV, ${\mathit{T}}_{1/2}$=163 ns) has been produced with the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{17}$O${,}^{18}$${\mathrm{F}}^{\mathit{m}}$${)}^{11}$B at E${(}^{17}$O)=70 MeV. The ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}_{}^{\mathit{m}}{}_{}{}^{}$ ions were focused onto a secondary target using a compact superconducting solenoid lens and scattering of ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}_{}^{\mathit{m}}{}_{}{}^{}$ from Au and carbon targets was observed. A conversion efficiency of >${10}^3$ ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}_{}^{\mathit{m}}{}_{}{}^{}$/s per 100 particle nanoamps of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ was obtained using a 1.1 mg/${\mathrm{cm}}^2$ natural carbon production target.

An intense beam (1.5×${10}^8$ particles/sec) of radioactive ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}_{}^{1+}{}_{}{}^{}$ ions (half-life: ${\mathit{T}}_{1/2}$=10 min) has been produced and accelerated to 0.65 MeV/nucleon, by coupling two cyclotrons with an electron cyclotron resonance ion source. This is the first time a short-lived radioactive ion beam has been produced by this method, at such an energy and with such a high intensity, a result which opens up a wide field in many applications. The first experiment along these lines will be the measurement of the cross section for the nuclear reaction ${}_{}{}^1{}_{}{}^{}\mathrm{H}$${(}^{13}$N,γ${)}^{14}$O which is the crucial reaction for the operation of the so-called hot CNO cycle in nuclear astrophysics.

Exclusive ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(${\mathrm{\pi }}^{\pm }$,${\mathrm{\pi }}^{\pm }$’p${)}^3$H spectra in the excitation energy range between 21.5 and 44 MeV in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ were measured at ${\mathit{T}}_{\mathrm{\pi }}$=180 MeV at several pion and proton angles. The cross section ratio ${\mathit{R}}_{\mathrm{\pi }\mathit{p}}$=σ(${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{+}$’p)/σ(${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{\mathrm{-}}$’p) was found to be between 1 and 2 near 22 MeV which is in the region of the ${\mathit{J}}^{\mathrm{\pi }}$=$2^{\mathrm{-}}$, T=0 state. Between 25 and 40 MeV in the continuum, which comprises the giant dipole resonance and broad $2^{\mathrm{-}}$ and $2^{+}$ states, ${\mathit{R}}_{\mathrm{\pi }\mathit{p}}$ ranges from 0.22 to 45 in sharp contrast to the predicted values of ≊1 from a model assuming the entire yield is due to the sequential decay of a state of good isospin, and 6 to 9 from a distorted-wave impulse approximation calculation assuming quasifree proton knockout.

A half-life of ${\mathit{T}}_{1/2}$=50(7) ps was measured for the $3_1^{\mathrm{-}}$ level in ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}$. The deduced B(E3) rate of 65(10) W.u. makes this $3_1^{\mathrm{-}}$→$0_1^{+}$ transition the fastest known. The results interpreted in terms of the random phase approximation and a deformed shell model suggest octupole instability around ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}$.

Strongly damped exit channels are identified in light-heavy-ion-induced reactions ${(}^9$Be, ${}_{}{}^{10,11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$${+}^{10,11}$B at ${\mathit{E}}_{\mathrm{lab}}$≤5 MeV/ nucleon), and their time scales are inferred from the isotropy of the angular distributions. These light compound systems seem able to reach statistical equilibrium within a fraction of a revolution of the dinuclear intermediate configuration. No simple correlation among the inelasticity of the process, mass transferred and ‘‘decay angle’’ is perceived.

We calculate the free interaction energy of two finite-temperature nuclei in the sudden approximation by using realistic semiclassical energy-density functionals. The fusion barriers for intermediate-size systems come over their ground state values for higher temperatures in such a way that there is a ‘‘critical temperature’’ above which fusion cannot occur. We discuss the implications of our results for the interpretation of empirical data.

From a comparison between the binding energies obtained in few-body systems for potentials operating first on relative S states only, and then on all orbitals we deduce the contribution of the l≠0 orbitals to the binding energy generated by local potentials. By a comparison of the exact solution of the Schrödinger equation to the one obtained from an integro-differential equation approach where only two-body correlations are taken into account one deduces the contribution of the N-body correlations (N>2).

Deuteron electrodisintegration d(e,e’) near threshold is calculated using the various energy-independent Bonn potential versions. At high momentum transfer they lead to rather different results compared to other realistic NN potentials. This can only be partly explained by a different D-state admixture strength. The potential effect is particularly strong for the transverse form factor, but is also present for the longitudinal one. The latter is influenced in a similar way as the longitudinal part of the elastic deuteron form factor A(${\mathit{q}}^2$) which we have considered in addition.

Differential cross sections are presented for the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p,2p)n at ${\mathit{T}}_{\mathit{p}}$=507 and 508 MeV for neutron recoil momenta ranging from 200 to 670 MeV/c. Data were taken for a wide range of kinematic conditions in which the relative kinetic energy between pairs of particles in the final state varied from 12 to 318 MeV. The data are compared with the impulse approximation (IA), which includes both p-p and p-n knockout terms, as well as with a nonrelativistic Glauber theory calculation (MS), which describes double scattering and final state interactions. The MS calculation agrees well with most of the data and is a significant improvement over the IA. Some of the data show evidence of virtual Δ excitation in the final state.

The inadequacy of standard few-body approaches in describing the πNN system has motivated searches for the responsible missing mechanism. In the case of πd scattering, it has recently been asserted that an additional short range ΔN interaction can account for essentially all the discrepancies between a few-body calculation and experimental data. This conclusion, however, has been based on calculations where a phenomenological ΔN interaction is added only in Born term to background few-body amplitudes. In the present work we investigate the effect of including such a ΔN interaction to all orders within a unitary few-body calculation of the πNN system. Besides testing the validity of adding the ΔN interaction in Born term in πd scattering, our fully coupled approach also enables us to see the influence of the same ΔN interaction on the processes NN→πd and NN→NN. For πd elastic scattering, we find that the higher order ΔN interaction terms can have as much influence on πd observables as the lowest order contribution alone. Moreover, we find that the higher order contributions tend to cancel the effect obtained by adding the ΔN interaction in Born term only. The effect of the same ΔN interaction on NN→πd and NN→NN appears to be as significant as in πd→πd, suggesting that future investigations of the short range ΔN interaction should be done in the context of the fully coupled πNN system.