Studies on the isospin of fragments resulting from the disassembly of highly excited large thermal-like nuclear emitting sources, formed in the ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ reaction at 35 MeV/nucleon beam energy, are presented. Two different decay systems (the quasiprojectile formed in midperipheral reactions and the unique source coming from the incomplete fusion of projectile and target in the most central collisions) were considered; these emitting sources have the same initial $N/Z$ ratio and excitation energy ${(E}^{*}\simeq 5–6\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{u}\mathrm{c}\mathrm{l}\mathrm{e}\mathrm{o}\mathrm{n}),$ but different size. Their charge yields and isotopic content of the fragments show different distributions. It is observed that the neutron content of intermediate mass fragments increases with the size of the source. These evidences are consistent with chemical equilibrium reached in the systems. This fact is confirmed by the analysis with the statistical multifragmentation model.

An extensive study of three-nucleon force effects in the entire phase space of the nucleon-deuteron breakup process, for energies from above the deuteron breakup threshold up to 200 MeV, has been performed. $3N$ Faddeev equations have been solved rigorously using the modern high precision nucleon-nucleon potentials AV18, CD Bonn, Nijm I, II, and Nijm 93, and also adding $3N$ forces. We compare predictions for cross sections and various polarization observables when $\mathrm{NN}$ forces are used alone or when the $2\pi$-exchange Tucson-Melbourne (TM) three nucleon force (3NF) was combined with each of them. In addition AV18 was combined with the Urbana IX 3NF and CD Bonn with the ${\mathrm{TM}}^{\prime }$ 3NF, which is a modified version of the TM 3NF, more consistent with chiral symmetry. Large but generally model dependent 3NF effects have been found in certain breakup configurations, especially at the higher energies, both for cross sections and spin observables. These results demonstrate the usefulness of the kinematically complete breakup reaction in testing the proper structure of $3N$ forces.

Selected $\mathrm{Nd}$ breakup data over a wide energy range are compared to solutions of Faddeev equations based on modern high precision $\mathrm{NN}$ interactions alone and adding current three-nucleon force models. Unfortunately currently available data probe phase space regions for the final three nucleon momenta which are rather insensitive to three-nucleon force (3NF) effects as predicted by current models. Overall there is good to fair agreement between present day theory and experiment but also some cases exist with striking discrepancies. Regions in the phase space are suggested where large 3NF effects can be expected.

Proton elliptic flow is studied as a function of impact parameter b, for two transverse momentum cuts in $2–6A\mathrm{GeV}$ $\mathrm{Au}+\mathrm{Au}$ collisions. The elliptic flow shows an essentially linear dependence on b (for $1.5<b<\mathrm{}8\mathrm{}\mathrm{fm})$ with a negative slope at $2A\mathrm{GeV},$ a positive slope at $6A\mathrm{GeV},$ and near zero slope at $4A\mathrm{GeV}.$ These selective flow measurements provide better understanding of the interplay of the different factors responsible for the generation of elliptic flow at AGS energies. In addition, extensive comparisons of the measured and calculated flow values indicate that such measurements offer much more stringent constraints for discriminating between various equations of state.

The ${}^{14}\mathrm{C}+\alpha$ decay of ${}^{18}\mathrm{O}$ has been studied via the ${}^{14}\mathrm{C}{(}^{18}\mathrm{O}{,}^{14}\mathrm{C}\alpha {)}^{14}\mathrm{C}$ reaction at 102 MeV. The excitation energy of the decaying ${}^{18}\mathrm{O}$ resonant particle has been determined following the coincident detection of the correlated ${}^{14}\mathrm{C}$ and $\alpha$ particles. A study of the angular correlations of the breakup fragments has allowed the spins of the decaying states to be investigated. The data provide evidence that a quasimolecular rotational band, identified by enhanced $\alpha$ decay, is observed in the reaction. Evidence is also presented for the ${}^{18}\mathrm{O}+\alpha$ decay of ${}^{22}\mathrm{Ne}.$

Lifetimes have been measured for states in the yrast (band 1) and an excited superdeformed band (band 2) in ${}^{196}\mathrm{Pb}.$ The excited band is thought to be built on an octupole vibration, rather than a quasiparticle excitation. Centroid shifts and line shapes of transitions in γ-ray coincidence spectra measured with the EUROBALL spectrometer have been analyzed. The transition quadrupole moments deduced from these data for the yrast and the excited superdeformed band are identical within the experimental uncertainties. This result shows that the excited band is not built on different deformation-driving orbitals compared to band 1. It is compatible with the previous suggestion of an octupole-vibrational excitation for the signature partner bands 2 and 3.

Multiplicity distributions and multiparticle interferometry are investigated by the use of a generating functional. A generating functional is obtained for a negative binomial distribution that describes experimental results well, and interferometry is studied using the generating functional. It is also shown that the multiplicity distributions of even a finite bin are in agreement with the negative binomial.

A pure p-wave ${\pi }^0$ condensation in the chiral $\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}\otimes \mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ model is studied within the relativistic mean-field approximation and its effect on the equation of state is compared with that of a pure s-wave $K^{-}$ condensation. To this end, three models are considered, which are distinguished from each other in the ways σ, ω, and ρ mesons contribute to the system’s energy. We find that, although the details of the result are model dependent, the ${\pi }^0$ condensation forming a standing wave is commonly observed in the intermediate region of density. In particular, in case ω’s mass is generated through coupling to σ, ${\pi }^0$ condensation reduces the system’s energy significantly. The pure ${\pi }^0$ condensation tends to be taken over by the pure uniform $K^{-}$ condensation at high densities because of the dominance of the KN sigma term.

By using techniques of unitarized chiral perturbation theory, where the $\Lambda \mathrm{}\left(1405\right)\mathrm{}$ and $\Lambda \mathrm{}\left(1670\right)\mathrm{}$ resonances are dynamically generated, we evaluate the magnetic moments of these resonances and their transition magnetic moment. The results obtained here differ appreciably from those obtained with existing quark models. The width for the $\Lambda \mathrm{}\left(1670\right)\mathrm{}\to \Lambda \mathrm{}\left(1405\right)\mathrm{}\gamma$ transition is also evaluated, leading to a branching ratio of the order of $2\times {10}^{-6}.$

It is shown that the empirical transition region near neutron number $N=90\mathrm{}$ can be described in terms of the crossing of configurations in a two-level system, as expected for a first order phase transition.

We investigate properties of $A=10\mathrm{}$ nuclei in the ab initio, no-core shell model using realistic Argonne and CD-Bonn nucleon-nucleon $\mathrm{}\left(\mathrm{NN}\right)\mathrm{}$ potentials and basis spaces through $9ħ\Omega$ (with basis dimensions reaching $5.5\times {10}^8).\mathrm{}$ Results for binding energies, excitation spectra (including negative parity and $2ħ\Omega$-dominated intruder states), electromagnetic properties, and the isospin-mixing correction of the ${}^{10}{\overrightarrow{\mathrm{C}}}^{10}\mathrm{B}$ Fermi transition are presented. For ${}^{10}\mathrm{B},$ these $\mathrm{NN}$ potentials produce a $J^{\pi }{T=1\mathrm{}}^{+}0$ ground state, contrary to the experimental $3^{+}0,$ a clear indication of the need for true three-body forces.

We report on shell-model calculations employing effective interactions derived from a new realistic nucleon-nucleon $\mathrm{}\left(\mathrm{NN}\right)\mathrm{}$ potential based on chiral effective-field theory. We present results for ${}^{18}\mathrm{O},$ ${}^{134}\mathrm{Te}$, and ${}^{210}\mathrm{Po}$. Our results are in excellent agreement with experiment indicating a remarkable predictive power of the chiral $\mathrm{NN}$ potential for low-energy microscopic nuclear structure.

The decay of the first two excited states of ${}^{17}\mathrm{Ne}$ ${(I}^{\pi }={\frac{3}{2}}^{-},$ ${\frac{5}{2}}^{-})$ has been studied via intermediate energy Coulomb excitation of a radioactive ${}^{17}\mathrm{Ne}$ beam on a ${}^{197}\mathrm{Au}$ target using a particle detector setup allowing a kinematically complete detection of the reaction products. Despite the first excited state being bound to single proton emission but unbound with respect to two proton emission, no evidence for a simultaneous two proton decay competing with the known $\gamma$ decay of the ${\frac{3}{2}}^{-}$ state could be observed. The ${\frac{5}{2}}^{-}$ state decays via sequential two-proton emission to the ground state of ${}^{15}\mathrm{O}.$ The transition matrix elements $B(E2,{\frac{1}{2}}^{-}\to {\frac{3}{2}}^{-}{)=66\mathrm{}}_{-25}^{+18\mathrm{}}\hspace{0.5em}{e}^2{\mathrm{fm}}^4$ and $B(E2,{\frac{1}{2}}^{-}\to {\frac{5}{2}}^{-}{)=124\mathrm{}(18)e}^2{\mathrm{fm}}^4$ have been deduced. From the nonobservation of the simultaneous two-proton emission of the ${\frac{3}{2}}^{-}$ state a lifetime limit ${\tau }_{2p}>26\mathrm{}\hspace{0.5em}\mathrm{ps}$ could be deduced in agreement with recent theoretical calculations.

Direct neutron capture on ${}^{62}\mathrm{Ni}$ is calculated in the DWBA and the Maxwellian averaged cross sections and astrophysical reaction rates in the energy range relevant for s-process nucleosynthesis are given. It is confirmed that the thermal value of the capture cross section contains a subthreshold resonance contribution. Contrary to previous investigations it is found that the capture at higher energies is dominated by p waves, thus leading to a considerably increased cross section at s-process energies and a modified energy dependence.

A study of available $\mathrm{}(t,p),$ $\mathrm{}(d,p),$ $B\left(E2\mathrm{}\right),$ and $\left(\overrightarrow{p}{,p}^{\prime }\right)$ results for ${}^{152}\mathrm{Sm}$ reveals the lack of an adequate experimental foundation for the recent interpretation of levels as multiple phonon structures based on the $0_2^{+}$ state at 685 keV. Each type of data agrees better with earlier descriptions, in which the calculated deformations are comparable to that of the ground state. Suggestions are made for experiments and calculations to help distinguish among the interpretations.

Complex poles of the unitarized $\pi -\pi$ scattering amplitude in nuclear matter are studied. Partial restoration of chiral symmetry is modeled by the decrease of in-medium pion decay constant $f_{\pi }^{*}.$ For large chiral restoration ${(f}_{\pi }^{*}{/f}_{\pi }\ll 1),$ second sheet poles in the scalar $\left(\sigma \right)$ and the vector $\left(\rho \right)$ mesons are both dictated by the Lambert W function and show universal softening as $f_{\pi }^{*}$ decreases. In-medium $\pi -\pi$ cross section receives substantial contribution from the soft mode and exhibits a large enhancement in low-energy region. Fate of this universality for small chiral restoration ${(f}_{\pi }^{*}{/f}_{\pi }\sim 1)$ is also discussed.

Single-particle resonant states in the continuum are determined by solving scattering states of the Dirac equation with proper asymptotic conditions in the relativistic mean field theory (RMF). The regular and irregular solutions of the Dirac equation at a large radius where the nuclear potentials vanish are relativistic Coulomb wave functions that are calculated numerically. Energies, widths, and wave functions of single-particle resonance states in the continuum for ${}^{120}\mathrm{Sn}$ are studied in the RMF with the parameter set of NL3. The isoscalar giant octupole resonance of ${}^{120}\mathrm{Sn}$ is investigated in a fully consistent relativistic random phase approximation. Comparing the results including full continuum states and only those single-particle resonances we find that the contributions from those resonant states dominate in the nuclear giant resonant processes.

Low-spin levels in ${}^{109}\mathrm{Sb}$ populated by ${}^{109}\mathrm{Te}$ beta decay are reported for the first time. Seven new levels are proposed, two below 1 MeV excitation energy. Spins and parities of ${(1/2\mathrm{}}^{+})$ and ${(3/2\mathrm{}}^{+}{,5/2\mathrm{}}^{+})$ are suggested for the low energy levels by comparison to beta feeding intensities and systematics. These results are compared with new calculated levels for ${}^{109}\mathrm{Sb}.$

Quadrupole excitations of neutron-rich nuclei are analyzed by using the linear response method in the quasiparticle random phase approximation (QRPA). The QRPA response is derived starting from the time-dependent Hartree-Fock-Bogoliubov (HFB) equations. The residual interaction between the quasiparticles is determined consistently from the two-body force used in the HFB equations, and the continuum coupling is treated exactly. Calculations are done for the neutron-rich oxygen isotopes. It is found that pairing correlations affect the low-lying states, and that a full treatment of the continuum can change the structure of the states in the giant resonance region.