Ground-state properties of spherical even-even nuclei $14<~Z<~28$ and $N=18,20,22\mathrm{}$ are described in the framework of relativistic Hartree-Bogoliubov (RHB) theory. The model uses the NL3 effective interaction in the mean-field Lagrangian, and describes pairing correlations by the pairing part of the finite range Gogny interaction D1S. Binding energies, two-proton separation energies, and proton rms radii that result from fully self-consistent RHB solutions are compared with experimental data. The model predicts the location of the proton drip line. The isospin dependence of the effective spin-orbit potential is discussed, as well as pairing properties that result from the finite range interaction in the $\mathrm{pp}$ channel.

Motivated by the recent high-spin data [1], we reinvestigate the structure of various bands in the nucleus ${}^{164}$Er in terms of the projected shell model, which describes all the bands by a single shell-model diagonalization. In the present work, it is found that an appropriate modification of the standard Nilsson (spin-orbit) parameters in the $N=5\mathrm{}$ proton shell is necessary in order to correctly describe both the yrast and the negative parity bands. With the same Hamiltonian, there are discrepancies to the data for some sidebands. To cure them, we would need an investigation of a larger scope than the present one.

For the hydrogenlike ${}^{229}{\mathrm{Th}}^{89+}$ ion, the rates of electromagnetic $M1\mathrm{}$ transitions between hyperfine structure levels, originating from the nuclear ${5/2}^{+}$ ground state and the first excited $3.5\pm 1.0\hspace{0.5em}\mathrm{eV}\hspace{0.5em}{3/2}^{+}$ isomeric state, are calculated. As a result of the mixing of the $F=2\mathrm{}$ components, these transitions turn out to be faster than the nuclear isomeric $\gamma$ transition in a bare nucleus by several orders of magnitude. The possibility of experimental observation of these transitions is discussed.

Shell corrections of finite, spherical, one-body potentials are analyzed using a smoothing procedure which properly accounts for the contribution from the particle continuum, i.e., unbound states. Since the plateau condition for the smoothed single-particle energy seldom holds, a new recipe is suggested for the definition of the shell correction. The generalized Strutinsky smoothing procedure is compared with the results of the semiclassical Wigner-Kirkwood expansion. A good agreement has been found for weakly bound nuclei in the vicinity of the proton drip line. However, some deviations remain for extremely neutron-rich systems due to the pathological behavior of the semiclassical level density around the particle threshold.

We present a calculation of asymmetric nuclear matter properties at zero temperature in a relativistic Brueckner-Hartree-Fock framework. Following other calculations the components of the self-energies are extracted by projecting on Lorentz-invariant amplitudes. It is shown that for asymmetric nuclear matter one needs a sixth invariant. We present a set of invariants which in the limit of symmetric nuclear matter reduces to the conventional set. We argue that the existence of such a properly behaving set is also crucial for the application of the projection method in symmetric nuclear matter. Results for the equation of state and other observables are presented. Special attention is paid to an analysis in terms of mean-field effective coupling constants. Apart from the usual ones we also find significant strength in the isovector scalar channel, which can be interpreted as an effective $\delta$ meson.

Different techniques for calculating effective operators within the framework of the shell model using the same effective interaction and the same excitation spaces are presented. Starting with the large-basis no-core approach, we compare the time-honored perturbation-expansion approach and a model-space truncation approach. Results for the electric quadrupole and magnetic dipole operators are presented for ${}^6\mathrm{Li}$. The convergence trends and dependence of the effective operators on differing excitation spaces and Pauli $Q$-operators are studied. In addition, the dependence of the electric-quadrupole effective charge on the harmonic-oscillator frequency and the mass number, for $A=5,6\mathrm{}$, is investigated in the model-space truncation approach.

Results of large-basis shell-model calculations for nuclei with $A=7\mathrm{}-11$ are presented. The effective interactions used in the study were derived microscopically from the Reid93 potential and take into account the Coulomb potential as well as the charge dependence of $T=1\mathrm{}$ partial waves. For $A=7\mathrm{}$, a $6ħ\Omega$ model space was used, while for the rest of the studied nuclides, the calculations were performed in a $4ħ\Omega$ model space. It is demonstrated that the shell model combined with microscopic effective interactions derived from modern nucleon-nucleon potentials is capable of providing good agreement with the experimental properties of the ground state as well as with those of the low-lying excited states.

The yields and velocity distributions of heavy residues and fission fragments from the reaction of 20 MeV/nucleon ${}^{197}\mathrm{Au}$ with ${}^{12}\mathrm{C}$ and ${}^{27}\mathrm{Al}$ have been measured using the MSU A1200 fragment separator. The mass and isotopic distributions of the reaction products are generally consistent with previously measured radiochemical data. One observes, especially for the Au+Al reaction, the production of very neutron deficient nuclides, possibly including “new” nuclei. The heavy-residue velocity distributions can be resolved into components due to fusionlike collisions (incomplete fusion, $v_{\mathrm{res}}{/v}_{\mathrm{cn}}\simeq 0.8)$ along with components due to more peripheral interactions. Fusionlike events were observed that lead to near- and trans-gold species. The observed mass and charge distributions of the fusionlike products, sorted by velocity, are compared with the results of simulations using PACE2 and GEMINI of the decay of the excited incomplete fusion products. The simulations, while reproducing the general features of the data, predict residue distributions that are too neutron deficient relative to the observed distributions. The observed yields of the trans-gold species are not predicted in the simulations.

We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident ${\pi }^{-}$ kinetic energy in the center of momentum angular range between $0°$ and $55°$. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.

Spin-isospin excitations in ${}^{12}$B and ${}^{12}$N have been studied using the ${}^{12}$C$(d$,${}^2$He)${}^{12}$B and ${}^{12}$C${(}^3$He,$t)$${}^{12}$N charge-exchange reactions at $\theta$ = 0$°$ and at $E_d$=200 MeV and $E$${(}^3$He)=450 MeV, respectively. Neutron decay from ${}^{12}$B to ${}^{11}$B and proton decay from ${}^{12}$N to ${}^{11}$C have been measured with detector arrays consisting of liquid-scintillation counters and silicon detectors, respectively. Microscopic structures of the spin-dipole resonances in ${}^{12}$B and ${}^{12}$N are discussed on the basis of the experimental observations of particle decays and their angular correlations.

The giant resonance region in ${}^{40}$Ca has been studied with inelastic electron scattering at the Mainz microton MAMI and the superconducting Darmstadt linear accelerator S-DALINAC for a momentum transfer range $q=0.25\mathrm{}-0.66\hspace{0.5em}{\mathrm{fm}}^{-1}$. Complete angular correlation functions for the coincident $\alpha$ decay into the ground state $\left({\alpha }_0\right)$ and first excited state $\left({\alpha }_1\right)$ of ${}^{36}$Ar have been measured. A model-independent multipole decomposition is presented for the ${\alpha }_0$ channel under the assumption of a mixture of $E0/E1/E2\mathrm{}$ strengths. It is demonstrated that this method can be extended to the ${\alpha }_1$ channel assuming that the relative weight of the allowed decay angular momenta is determined by transmission coefficients and for a specific choice of relative phases between multipole amplitudes suggested by the data. The resulting distributions of isoscalar $E0\mathrm{}$ and $E2\mathrm{}$ strengths for the ${\alpha }_0$ and ${\alpha }_1$ channels are tested against microscopic calculations including coupling to the continuum and complex configurations of the 1p-1h$\otimes$phonon type. Assuming statistical decay the total isoscalar $E0\mathrm{}$ response can be reconstructed. An exhaustion of 44.2(8.8)% of the energy-weighted sum rule for the isoscalar giant monopole resonance is found in the excitation energy interval $11-19$ MeV. The $B\left(E0\mathrm{}\right)\mathrm{}$ strength distribution is in fair agreement with recent $(\alpha ,{\alpha }^{\prime })$ measurements under extreme forward angles suggesting a centroid energy of about $17-18$ MeV.

The two-fragment angle correlation functions of mass-symmetric ternary fragment events from highly excited nuclei produced in ${}^{40}\mathrm{Ar}{+}^{209}\mathrm{Bi}{/}^{197}\mathrm{Au}{/}^{159}\mathrm{Tb}{/}^{115}\mathrm{In}$ reactions at 25 MeV/nucleon are used to extract the mean time interval in cascade emissions $\left(\tau \right)$ of intermediate mass and heavy mass fragments (mass number greater than 20). It is shown that the mean time interval decreases from the characteristic time $\tau =2000\mathrm{}–1000\mathrm{fm}/c$ for the Ar+Bi and Ar+Au reactions to $\tau =750\mathrm{}\hspace{0.5em}\mathrm{fm}/c$ for the Ar+Tb reaction and to $\tau =50\mathrm{}\hspace{0.5em}\mathrm{fm}/c$ for the Ar+In reaction. The decay mode of hot nuclei evolves from cascade fission to simultaneous multifragmentation as the excitation energy increases and the mass of hot nuclei decreases.

The reaction ${}^{40}\mathrm{Ca}{(p,p}^{\prime }{p}^{″})$ was investigated at an incident energy of 392 MeV. The energy and angular distributions are found to be consistent in shape as well as in absolute magnitude with the prediction of a reaction mechanism based on rescattering from a seminal knockout process. In this mechanism the struck nucleon behaves like an intranuclear projectile and initiates further rescatterings with the remainder of the target nucleus that is reminiscent of the interaction of a free projectile of similar kinetic energy. These results provide strong evidence for the validity of conclusions derived from earlier investigations at lower incident energies. The considerable uncertainty exhibited in previous work in the quantitative relationship between the yields of the initial knockout events and the secondary rescattering processes has been resolved in this study. Also, the participation of knockout from deeply bound shell-model orbitals has been clarified.

Double differential cross sections from the ${}^{120}\mathrm{Sn}{\mathrm{}(n,p)\mathrm{}}^{120}\mathrm{In}$ and ${}^{181}\mathrm{Ta}{\mathrm{}(n,p)\mathrm{}}^{181}\mathrm{Hf}$ reactions at 298 MeV and the ${}^{238}\mathrm{U}{\mathrm{}(n,p)\mathrm{}}^{238}\mathrm{Pa}$ reaction at 318 MeV have been measured for excitation energies up to 50 MeV in the residual nucleus. These data, together with the previously published data from the ${}^{90}\mathrm{Zr}{\mathrm{}(n,p)\mathrm{}}^{90}\mathrm{Y}$ and ${}^{208}\mathrm{Pb}{\mathrm{}(n,p)\mathrm{}}^{208}\mathrm{Tl}$ reactions at 198 MeV, have been analyzed for spin-isovector resonances of multipolarities less than 7, using the multipole decomposition method. The strengths due to spin-isovector excitations of multipolarity less than 4 have been extracted. The anomalous behavior of the extracted spin-isovector quadrupole strength with target mass number is discussed with reference to the calculations of Leonardi et al. The cross section due to quasifree processes was calculated and subtracted from the data. The data after this subtraction were reanalyzed for spin-isovector resonances and the strengths due to multipolarities up to 3 were extracted. The strengths due to spin-isovector dipole and octupole excitations were compared to values calculated, for 1ħω transitions only, using the sum rules of Macfarlane. The behavior with target mass number is well represented by these sum rules.

Total and differential cross sections for the reaction ${}^2\mathrm{H}(\gamma ,{\pi }^0)$ have been investigated within 20 MeV of threshold using the tagged photon facility at SAL in conjunction with the ${\pi }^0$ spectrometer IGLOO. The differential measurements are the first to be reported in the threshold region, while the total cross section is a significant improvement over the only previous measurement. We give the first determination of the electric dipole amplitude for ${\pi }^0$ photoproduction from the deuteron in the threshold region. The threshold amplitude ${(E}_d)$ has recently been calculated within the framework of chiral perturbation theory (ChPT). The present result for $E_d$ falls about 20% below the ChPT value. We confirm the predicted sign (negative). Above threshold we find no evidence for a unitarity cusp such as is observed in the dipole amplitude for ${}^1\mathrm{H}(\gamma ,{\pi }^0).\mathrm{}$ Finally, the elementary $P$-wave amplitude $P_1^{\mathrm{}(+)\mathrm{}}$ as deduced from the angular distributions is compared with ChPT predictions. A substantial discrepancy with theory is evident, perhaps a signal of two-body effects.

The damping widths of giant resonances is calculated using a scheme developed for multistep compound processes. The results were found to be reasonable and compare well to those indirectly extracted from data.

We present an alternative theoretical formulation of the Coulomb dissociation process. We apply the formalism to the deuteron as an example of a weakly bound two-body composite nucleus with a charged core and a neutral valence particle and for which exclusive experimental data exist in an appropriate kinematical regime. The theoretical scheme assumes that the projectile excitation is predominantly to states with low internal energy and is expected to be applicable at incident projectile energies of tens of MeV per nucleon and above. A readily calculable expression for the quantum mechanical breakup transition amplitude is obtained without the use of the distorted-wave Born approximation weak channel coupling approximation or of additional approximations for finite-range effects. Calculations are presented, analyzed, and compared with high precision, kinematically complete, measurements of elastic deuteron dissociation into very forward scattering angles. The calculations and data support the importance of the Coulomb breakup mechanism under these kinematical conditions.

We investigate two aspects of the Glauber model for $\mathrm{}(p,d)\mathrm{}$ transfer reactions on nuclei. The first one is connected with the violation of angular momentum conservation at the transition vertex inherent to straight line propagation. This can be cured by introducing a different impact parameter in the entrance and exit channels. We give an estimate of this effect in the case of $\mathrm{}(p,d)\mathrm{}$ reactions on ${}^{12}\mathrm{C}$. Second, the formalism is applied to single neutron halo nuclei. We study the sensitivity of the $\mathrm{}(p,d)\mathrm{}$ cross sections to the radial dependence of the halo wave function and to its rms radius.

Calculations in the quantum statistical model show that the number of intermediate mass fragments produced from hot nuclei scales according to mass for relatively heavy emitting systems. Contrary to experimental observation, discernible deviations from scaling are observed for light sources. Similar scaling behavior is seen for the total number of charged particles produced as well as for the individual fragment species. The scaling pattern remains unaltered with the inclusion of collective radial flow. The calculated results with a moderate amount of collective flow energy in the total excitation are in consonance with the experimental data. Calculations in the model of sequential binary decay with temperature-dependent barriers are also found to reproduce scaling quite well.

Having first performed a Monte Carlo simulation to justify the analysis technique to be used, we then analyze the Bose-Einstein correlation functions from CERN experiment NA44 in the context of the core-halo model. Although experimental resolution and error bar distribution prevents a direct observation of the halo structure, the values for the core radius and the core fraction of pions can be obtained in a straightforward manner. These are found to be independent of the structure of the correlation function at small relative momenta of $Q<\mathrm{}50\mathrm{}$ MeV. Hence, the $\omega$ meson decay products do not distort the Gaussian shape of the Bose-Einstein correlation function in $\mathrm{S}+\mathrm{P}\mathrm{b}\to \pi +\pi +X$ reaction at CERN SPS. As we find that the “model-independent” Hanbury-Brown–Twiss radii yield results that are quantitatively as well as qualitatively unreliable for systems with long-lived resonances, we present their corrected form that applies for correlation functions with $\lambda \left(\mathbf{K}\right)<\mathrm{}1\mathrm{}$.