Kaon photoproduction on the deuteron is studied with respect to a specific two-body contribution, namely a pion mediated production process, besides other final state interaction contributions from kaon-nucleon and hyperon-nucleon scattering. In this process, a pion is first photoproduced on one nucleon and then interacts with the spectator nucleon in a strangeness exchange reaction leading to a kaon and a hyperon. A sizeable effect from this pion mediated contribution is found, considerably larger than the previously studied hyperon-nucleon rescattering, whereas kaon-nucleon rescattering is much less important. Besides total and semi-inclusive differential cross sections, tensor target asymmetries are studied with respect to the influence of such interaction effects.

Parity quantum numbers for dipole-excited states of the nuclei ${}^{92}\mathrm{Zr}$ and ${}^{96}\mathrm{Mo}$ have been determined from azimuthal asymmetries of nuclear resonance fluorescence intensities induced with the linearly polarized photon beam of the $\mathrm{HI}\gamma \mathrm{S}$ facility at Duke University. This parity information is crucial for an interpretation of the investigated $J=1$ states as two-phonon excitations originating from inhomogeneous phonon coupling.

We have studied the primary and secondary $\gamma$ rays (414 in ${}^{59}\mathrm{Ni}$, 390 in ${}^{60}\mathrm{Ni}$, and 240 in ${}^{61}\mathrm{Ni}$) following thermal-neutron capture by the stable ${}^{58}\mathrm{Ni}$, radioactive ${}^{59}\mathrm{Ni}$, and stable ${}^{60}\mathrm{Ni}$ isotopes. Most of these $\gamma$ rays have been incorporated into the corresponding level schemes consisting of 65 levels in ${}^{59}\mathrm{Ni}$, 88 levels in ${}^{60}\mathrm{Ni}$, and 40 levels in ${}^{61}\mathrm{Ni}$. The measured neutron separation energies ($S_n$ in keV) for ${}^{59}\mathrm{Ni}$, ${}^{60}\mathrm{Ni}$, and ${}^{61}\mathrm{Ni}$ are, respectively, $8999.28\pm 0.05$, $\mathrm{11\hspace{0.17em}387.73}\pm 0.05$, and $7820.11\pm 0.05$. The measured thermal-neutron capture cross sections (in barns) for ${}^{58}\mathrm{Ni}$, ${}^{59}\mathrm{Ni}$, and ${}^{60}\mathrm{Ni}$ are, respectively, $4.13\pm 0.05$, $73.7\pm 1.8$, and $2.34\pm 0.05$. In all three cases, primary electric-dipole $\left(E1\right)$ transitions account for the bulk of the total capture cross section. We have calculated these $E1$ partial cross sections (in ${}^{59}\mathrm{Ni}$ and ${}^{61}\mathrm{Ni}$) using direct-capture theory and models of compound-nuclear capture. The agreement between theory and experiment is good. The experimental level schemes have been compared with the results from a large-basis shell-model calculation. The agreement was also found to be quite good.

The low-lying dipole strength distributions in the odd-mass isotopes ${}^{135,137}\mathrm{Ba}$ were studied in nuclear resonance fluorescence experiments (NRF) performed at the Stuttgart Dynamitron facility using bremsstrahlung beams with end point energies of 4.1, 3.1, and $2.5\mathrm{MeV}$. Numerous excited states, most of them unknown so far, were observed in the excitation energy range up to $4\mathrm{MeV}$. Detailed spectroscopic information has been obtained on excitation energies, decay widths, decay branching ratios, and transition probabilities. The results for ${}^{137}\mathrm{Ba}$ are compared with calculations in the framework of the Quasiparticle-Phonon Model. The new data for ${}^{135,137}\mathrm{Ba}$ complete the systematics of low-lying dipole excitations as observed for the even Ba isotopes ${}^{134,136,138}\mathrm{Ba}$ in previous NRF experiments in Stuttgart. The complete systematics within the Ba isotopic chain, exhibiting a nuclear shape transition, is discussed with respect to $E1$ two-phonon excitations, $M1$ scissors mode excitations, and in regard to the new critical point symmetries.

The recent laser spectroscopic measurements of nuclear root-mean-square charge radii on a chain of Zr isotopes exhibit a rich structure. A prominent kink is observed at ${}^{90}\mathrm{Zr}$ and a sharp change is noticed between ${}^{98}\mathrm{Zr}$ and ${}^{100}\mathrm{Zr}$, in the neutron rich region. In the present work, the ground state properties of these nuclei are calculated in the relativistic mean field (RMF) framework. The calculations are in good accord with the experiment. The RMF densities are folded with the extended Jeukenne, Lejeune, and Mahaux energy and density dependent nucleon-nucleon interaction to yield the semimicroscopic optical potential which in turn is used to calculate the elastic scattering cross sections for 50 MeV proton scattering from a chain of Zr isotopes. The differential cross sections obtained from the calculations agree remarkably well with the experiment. The calculation reveals a correlation between the mean-square charge radii and the corresponding reaction cross sections for $A⩾88$. There is a monotonic increase in ${\sigma }_R$ from $A=84$ to 106 with the hint of a slight jump from $A=98$ to $A=100$.

The dynamics of embryonic bubbles in overheated, viscous, and non-Markovian nuclear matter is studied. We show that the memory and the Fermi surface distortions significantly affect the hindrance of bubble collapse and determine characteristic oscillations of the bubble radius. These oscillations occur due to the additional elastic force induced by the memory integral.

In order to study the $\Sigma$-nucleus optical potential, we measured inclusive $({\pi }^{-},K^{+})$ spectra on medium-to-heavy nuclear targets $\mathrm{C}{\mathrm{H}}_2$, Si, Ni, In, and Bi. The $\mathrm{C}{\mathrm{H}}_2$ target was used to calibrate the excitation energy scale by using the elementary process $p+{\pi }^{-}\to K^{+}+{\Sigma }^{-}$, where the C spectrum was also extracted. The calibration was done with $\pm 0.1\mathrm{MeV}$ precision. The angular distribution of the elementary cross section was measured and agreed well with the previous bubble chamber data, but with better statistics, and the magnitudes of the cross sections of the measured inclusive $({\pi }^{-},K^{+})$ spectra were also well calibrated. All of the inclusive spectra were found to be similar in shape at a region near to the ${\Sigma }^{-}$ binding energy threshold, showing a weak mass-number dependence on the magnitude of the cross section. The measured spectra were compared with a theoretical calculation performed within the framework of the distorted-wave impulse approximation. It has been demonstrated that a strongly repulsive $\Sigma$-nucleus potential with a nonzero size of the imaginary part is required to reproduce the shape of the measured spectra.

Using an analytical parametrization of hadronic freeze-out in relativistic heavy ion collisions, we present a detailed study of the connections between features of the freeze-out configuration and physical observables. We focus especially on anisotropic freeze-out configurations (expected in general for collisions at finite impact parameter), azimuthally sensitive Hanburry-Brown-Twiss interferometry, and final-state interactions between nonidentical particles. Model calculations are compared with data taken in the first year of running at RHIC; while not perfect, good agreement is found, raising the hope that a consistent understanding of the full freeze-out scenario at RHIC is possible, an important first step towards understanding the physics of the system prior to freeze-out.

The theoretical nuclear physics predictions and experimental results on antiprotonic atoms lead to different proton and neutron spatial distributions. At CERN SPS energies production of positive and negative pions differs for $pp,pn,np$, and $nn$ scattering. These two facts lead to an impact-parameter dependence of the ${\pi }^{+}$ to ${\pi }^{-}$ ratio in ${}^{208}\mathrm{Pb}+{}^{208}\mathrm{Pb}$ collisions. A recent experiment at CERN seems to qualitatively confirm these predictions. The results for two models considered are almost identical. This may open a new possibility for determination of the neutron density distribution in nuclei.

An analysis of $K^{+}\text{‐}d$ total cross section data is undertaken to explore possible effects of the recently observed resonance in the $S=+1$ hadronic system with mass around $1.55\mathrm{GeV}$. It is found that a structure corresponding to the resonance is visible in the data. The width consistent with the observed deviation from background is found to be $0.9\pm 0.3\mathrm{MeV}$ and the mass is $1.559\pm 0.003\mathrm{GeV}∕c^2$ for spin parity ${\frac{1}{2}}^{+}$ and $1.547\pm 0.002\mathrm{GeV}∕c^2$ for ${\frac{1}{2}}^{-}$. The errors are one standard deviation and statistical only.

Two new facilities have recently been proposed to measure low energy neutrino-nucleus cross sections, the $\nu$-Spallation Neutron Source and low energy beta beams. The former produces neutrinos by muon decay at rest from stopped pions, while the latter produces neutrinos from the beta decays of accelerated ions. These facilities can be used to measure cross sections for neutrino energies in the range of tens of mega-electron-volts, which are of interest for supernova studies. In this energy range there are many different components to the nuclear response and this makes the theoretical interpretation of the results of such an experiment complex. We examine the case of lead and suggest that the response can be disentangled by breaking the electron spectrum down into the parts produced in coincidence with one or two neutrons, running a beta beam at more than one energy, comparing the spectra produced with pions, and a beta beam or any combination of these.

The previous Faddeev calculation of the two-alpha plus $\Lambda$ system for ${}_{\Lambda }{}^9\mathrm{B}\mathrm{e}$ is extended to incorporate the spin-orbit components of the ${\mathrm{SU}}_6$ quark-model (QM) baryon-baryon interactions. We employ the Born kernel of the QM $\Lambda N$ $LS$ interaction and generate the spin-orbit component of the $\Lambda \alpha$ potential by $\alpha$-cluster folding. The Faddeev calculation in the $jj$-coupling scheme implies that the direct use of the QM Born kernel for the $\Lambda N$ $LS$ component is not good enough to reproduce the small experimental value $\Delta E_{\ell s}^{\mathrm{expt}}=43\pm 5\mathrm{keV}$ for the $5∕2^{+}$-$3∕2^{+}$ splitting. This procedure predicts 3–5 times larger values in the models FSS and fss2. The spin-orbit contribution from the effective meson-exchange potentials in fss2 is argued to be unfavorable to the small $\ell s$ splitting, through the analysis of the Scheerbaum factors for the single-particle spin-orbit potentials calculated in the $G$-matrix formalism.

It is shown that the existing yrast $B\left(E2\right)$ values [especially the $B\left(E2;4_1^{+}\to 2_1^{+}\right)∕B\left(E2;2_1^{+}\to 0_1^{+}\right)$ ratio] in ${}^{98}\mathrm{Ru}$ are highly anomalous and cannot be plausibly interpreted with existing models. A survey of all even-even nuclei from $40⩽Z⩽80$ shows that this phenomenon is rare in collective nuclei. It occurs to a much lesser extent in ${}^{114}\mathrm{Te}$, ${}^{114}\mathrm{Xe}$, and possibly a few other nuclides. The combination of vibrational-like energies and nonvibrational $B\left(E2\right)$ values perhaps points to a different kind of vibrational behavior.

The reactions $\gamma p\to K^{+}\Lambda$ and $\gamma d\to K^{+}\Lambda n$ have been investigated over the energy range from $E_{\gamma }=1.0\mathrm{GeV}\text{to}{E}_{\gamma }=1.8\mathrm{GeV}$ in a tree-level effective Lagrangian model that incorporates most of the well-established resonances of spins $\frac{1}{2}$ and $\frac{3}{2}$ below $1.9\mathrm{GeV}$. Several sets of values for the resonance couplings are generated by fitting empirical cross section curves for the proton reaction at three different energies. Results obtained with a number of these fits are then presented for the cross sections and several single polarization observables for both reactions. The deuteron reaction is treated within the impulse approximation with final state interactions incorporated by means of a nonrelativistic overlap integral in momentum space. We explore the dependences of the calculated quantities on several facets of the model, including the particular resonance fit employed, the treatment of the spin $\frac{3}{2}$ resonance propagator, the prescription used for the resonance widths, and for the deuteron reaction, the final state interaction and deuteron wave function employed. We find that for neither reaction are the cross sections very sensitive to any of the model details. The polarization observables, on the other hand, are quite sensitive to certain model details, particularly to the resonance model employed and to the prescription used for the resonance widths. In general the polarization observables in the proton reaction are more sensitive to model details than the polarization observables in the deuteron reaction. The calculated deuteron observables are not strongly dependent on either the final state interaction or the deuteron wave function employed.

We discuss the target and beam normal spin asymmetries in elastic electron-nucleon scattering which depend on the imaginary part of two-photon exchange processes between electron and nucleon. We express this imaginary part as a phase space integral over the doubly virtual Compton scattering tensor on the nucleon. We use unitarity to model the doubly virtual Compton scattering tensor in the resonance region in terms of $\gamma *N\to \pi N$ electroabsorption amplitudes. Taking those amplitudes from a phenomenological analysis of pion electroproduction observables, we present results for beam and target normal single spin asymmetries for elastic electron-nucleon scattering for beam energies below 1 GeV and in the 1–3 GeV region, where several experiments are performed or are in progress.

The liquid-gas phase transition in strange hadronic matter is studied utilizing an extended Furnstahl-Serot-Tang model with nucleons and hyperons. The system is treated as of two components. The phase transition is analyzed by investigating the stability of the system and Gibbs conditions for phase equilibrium. A two-dimensional binodal surface resulting from the two-phase equilibrium—namely, the phase boundary—is obtained. For each temperature ranging from $T=8$ to 12 MeV, a limit pressure on the binodal surface section is found, while a critical point is spotted for the temperature around $T=13\mathrm{MeV}$. Maxwell constructions are also illustrated to give a vivid description of the course of the phase transition. Moreover, the entropy per baryon and heat capacity per baryon as functions of temperature are examined. The entropy is continuous during the phase transition but the heat capacity is discontinuous, indicating that the phase transition is of second order. By these efforts, the liquid-gas phase transition can be concluded to exist in strange hadronic matter.

We present an accurate method of simultaneously treating nuclear and Coulomb breakup of weakly bound nuclei by means of the method of continuum discretized coupled channels with the pseudostate method of discretization. As $L^2$-type basis functions of expansion of bound and continuum states of the projectile, we take complex-range Gaussian functions which in good approximation form a complete set in a large configuration space which is important for both nuclear- and Coulomb-breakup processes. The accuracy of the method is tested quantitatively for ${}^8\mathrm{B}+{}^{58}\mathrm{Ni}$ scattering at 25.8 MeV.

The inelastic neutral reaction of neutrino on ${}^4\mathrm{He}$ is calculated microscopically, including full final state interaction among the four nucleons. The calculation is performed using the Lorentz integral transform method and the hyperspherical-harmonic effective interaction approach, with a realistic nucleon-nucleon interaction. A detailed energy dependent calculation is given in the impulse approximation. With respect to previous calculations, this work predicts an increased reaction cross section by $10–30\%$ for neutrino temperature up to $15\mathrm{MeV}$.

Nucleonic ${}^{1}S_0$ and ${}^{3}PF_2$ pairing gaps in neutron stars are determined and their sensitivity to medium effects realized through nucleonic three-body forces, and the presence of hyperons is explored.

The nucleon-nucleon $\left(NN\right)$ interaction is constructed by means of the $J$-matrix version of inverse scattering theory. Ambiguities of the interaction are eliminated by postulating tridiagonal and quasitridiagonal forms of the potential matrix in the oscillator basis in uncoupled and coupled waves, respectively. The obtained interaction is very accurate in reproducing the $NN$ scattering data and deuteron properties. The interaction is used in the no-core shell model calculations of ${}^3\mathrm{H}$ and ${}^4\mathrm{He}$ nuclei. The resulting binding energies of ${}^3\mathrm{H}$ and ${}^4\mathrm{He}$ are very close to experimental values.