Baryon-baryon interactions for the complete baryon octet ${(B}_8)$ are investigated in a unified framework of the resonating-group method, in which the spin-flavor ${\mathrm{SU}}_6$ quark-model wave functions are employed. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon interaction. We then proceed to explore $B_8{B}_8$ interactions in the strangeness $S=-2,$ $-3,$ and $-4$ sectors. The S-wave phase-shift behavior and total cross sections are systematically understood by (1) the spin-flavor ${\mathrm{SU}}_6$ symmetry, (2) the special role of the pion exchange, and (3) the flavor symmetry breaking.

A simple compact correlation of the energies of the lowest $0^{+}$ excitation with the yrast energy ratio $R_{4/2}(\mathrm{g}.\mathrm{s}.\mathrm{})\equiv {E(4\mathrm{}}_1^{+}{)/E(2\mathrm{}}_1^{+})$ is found to characterize all collective nuclei, regardless of structure. This correlation can be reproduced by interacting bosom approximation calculations. Collective signature observables for the states based on $0_2^{+}$ excitations indicate a different structure than for the ground state configuration but systematic inconsistencies in their global behavior and discrepancies with calculations prevent a definite interpretation.

We present a new method for analyzing directed and elliptic flow in heavy-ion collisions. Unlike standard methods, it separates the contribution of flow to azimuthal correlations from contributions due to other effects. The separation relies on a cumulant expansion of multiparticle azimuthal correlations, and includes corrections for detector inefficiencies. This new method allows the measurement of the flow of identified particles in narrow phase-space regions, and can be used in every regime, from intermediate to ultrarelativistic energies.

The nucleus ${}^{46}\mathrm{V}$ has been studied in the reaction ${}^{24}\mathrm{Mg}{(}^{28}\mathrm{Si},\alpha {pn)}^{46}\mathrm{V}$ at $115\hspace{0.5em}\mathrm{MeV}$ beam energy, using both Au and Pb backed targets. Lifetimes were obtained for $14$ levels with DSAM analysis. Experimental $B\left(E2\mathrm{}\right)\mathrm{}$ reduced transition probabilities are well reproduced by the large scale shell model. The observed levels could be organizied in bands with a rather good K value.

Prompt and delayed $\gamma$ rays originating from the neutron deficient nucleus ${}^{183}\mathrm{Tl}$ have been observed using the recoil-decay tagging and recoil gating techniques. The band-head energy of the prolate $\pi i_{13/2}$ yrast band has been determined. The yrast structure has also been confirmed up to the ${(33/2\mathrm{}}^{+})$ state. In addition, a candidate for the ${(11/2\mathrm{}}^{-})$ level based on the $\pi {(h}_{11/2}{)}^{-1}$ configuration has been observed.

The tunneling of a quasibound dinuclear system along the main radial mode is studied for the case of cold fission when the very small excitation energy present in the decaying system is distributed among molecular type transversal collective degrees of freedom. Such a collective mode has typical oscillation periods much smaller than the tunneling time of the main radial mode and, therefore, we discuss various approaches that are suitable in dealing with this problem. The modified penetrabilities are obtained at first by solving the coupled set of Schrödinger equations in the adiabatic and the diabatic approximations. The comparison with the one-dimensional penetrability is done also in the frame of the Feynman path integral formalism for a very large inertial mass and small transversal vibrations frequency. In all cases the coupling of the radial(fission) mode to the transversal degrees of freedom leads to a change in the tunneling probability that is, however, not so strong to determine significant variations in the fission lifetime.

Total reaction cross sections ${\sigma }_R$ of all particle-stable Be isotopes on Si, and several of their neutron-removal cross sections ${\sigma }_{-\mathrm{xn}},$ were measured near $(30\mathrm{}–60)A\hspace{0.5em}\mathrm{MeV}$ by injecting magnetically separated, focused, monoenergetic secondary beams of these projectiles into a telescope containing nine Si transmission detectors. Similar measurements were made for ${}^{10-12}\mathrm{Be}$ on Pb, by placing Pb targets between the Si detectors of another telescope. A Glauber analysis of the $\mathrm{Be}+\mathrm{Si}$ ${\sigma }_R$ data, including only nuclear forces, yields rms radii for the Be isotopes in general agreement with those found by other workers. Similar calculations underpredict the ${\sigma }_R$ data for $\mathrm{Be}+\mathrm{Pb},$ showing the importance of electromagnetic dissociation. A simple microscopic theory reproduces the n-removal cross sections for ${}^{11}\mathrm{Be}$ and ${}^{14}\mathrm{Be}$ on Si, but overpredicts n removal for ${}^{11}\mathrm{Be}$ on Pb. For ${}^{12}\mathrm{Be}$ incident upon both Si and Pb targets, ${\sigma }_{-2n}$ significantly exceeds ${\sigma }_{-n},$ as is expected since $1n$ removal leaves the weakly bound halo nucleus ${}^{11}\mathrm{Be}.$ A similar effect for ${}^{10}\mathrm{Be}$ on Si is attributed to the weak binding of the last neutron of ${}^9\mathrm{Be};$ however, for ${}^{10}\mathrm{Be}+\mathrm{Pb},$ ${\sigma }_{-n}$ slightly exceeds ${\sigma }_{-2n}.$

The $\eta$-deuteron scattering amplitude is calculated with a recent K-matrix model of $\eta N$ interactions. The existence of a narrow virtual state in the $\eta$-deuteron system is inferred. This state couples strongly to the $\eta d$ channel, but its effect on final state interactions in the $p\overrightarrow{n}\eta d$ reaction is shown to be rather weak. Fairly large $\eta N$ scattering lengths are allowed by the experimental data.

Cross sections were measured at forward angles including $0°$ in the ${}^9\mathrm{Be}{(}^3\mathrm{He},t)$ reaction at $E/A=150\mathrm{}\hspace{0.5em}\mathrm{MeV}.$ Evidence is given for a state in ${}^9\mathrm{B}$ at $3.82{\pm }_{0.22}^{0.23}\hspace{0.5em}\mathrm{MeV}$ with $\Gamma =1330\mathrm{}{\pm }_{360}^{620}\hspace{0.5em}\mathrm{keV}.$ Further, the data are consistent with the presence of another state at $1.80{\pm }_{0.16}^{0.22}\hspace{0.5em}\mathrm{MeV}$ with $\Gamma =600\mathrm{}{\pm }_{270}^{300}\hspace{0.5em}\mathrm{keV}.$

The capability of the spin– and particle-number–projected generator coordinate method (PGCM) is studied on the basis of the single-$j$ shell model with monopole-pairing plus quadrupole-quadrupole interaction. The PGCM generates ground and excited states which attain an excellent agreement with the exact solutions of the shell model. It is also found that the projections of spin and particle number drive the system toward large triaxial shapes, irrespective of the shell fillings.

In this work we calculate the caloric curve (excitation energy per particle as a function of temperature) for finite nuclei within the nonlinear Walecka model for different proton fractions. It is shown that the caloric curve is sensitive to the proton fraction. Freeze-out volume effects in the caloric curve are also studied.

In response to recent experimental studies we investigate Coulomb distortion effects on ${(e,e}^{\prime })$ reactions from medium and heavy nuclei for the case of electrons and positrons. We extend our previously reported full distorted-wave Born approximation treatment of Coulomb distortions to the case of positrons for the ${}^{208}\mathrm{Pb}$ ${(e,e}^{\prime })$ reaction in the quasielastic region for a particular nuclear model. In addition, we use previously reported successful approaches to treating Coulomb corrections in an approximate way to calculate the Coulomb distortion effects for ${(e,e}^{\prime })$ reactions for both electrons and positrons for the case of a simple nuclear model for quasielastic knockout of nucleons. With these results in hand we develop a simple ad hoc approximation for use in analyzing experiments, and discuss methods of extracting the “longitudinal structure function” which enters into evaluation of the Coulomb sum rule. These techniques are generally valid for lepton induced reactions on nuclei with momentum transfers greater than approximately 300 MeV/c.

Calculations for a set of nuclear multifragmentation data are made using a canonical and a grand canonical model. The physics assumptions are identical but the canonical model has an exact number of particles, whereas the grand canonical model has a varying number of particles, hence, is less exact. Interesting differences are found.

An experiment on nuclear excitation by electronic transition (NEET) induced by deexcitations of the excited atomic states was performed on ${}^{189}\mathrm{Os}.$ Osmium targets were bombarded with both a white beam and with a monochromatic 115 keV x ray beam to produce K vacancies in Os atoms. Online K x-ray spectra were measured with a Ge detector and the L x rays emitted from the 30.814 keV isomer state in the ${}^{189}\mathrm{Os}$ nucleus were measured offline. The NEET probability obtained from the monochromatic beam experiment was deduced to be less than $4.1\times {10}^{-10}$ per created K hole. This value is much lower than the values measured so far. The white beam experiment shows that these high probabilities of the NEET process in ${}^{189}\mathrm{Os},$ which were obtained by irradiation with white x-ray and bremsstrahlung x-ray beams, results mainly in a contribution from direct nuclear photoabsorption into the 69.537 keV state in ${}^{189}\mathrm{Os}.\mathrm{}$

We consider the process of low-energy η-nucleon interactions in the framework of heavy baryon chiral perturbation theory with the $S_{11}\mathrm{}\left(1535\right)\mathrm{}$ resonance treated as an independent field. We include leading and next-to-leading terms in chiral expansion of the amplitudes of the pion induced η-meson production and elastic η-nucleon scattering.

A direct method is developed to reconstruct the equation of state for high-density nuclear matter from the relationship between any two properties of neutron stars, such as masses, radii, moments of inertia, baryonic masses, binding energies, gravitational redshifts, and their combinations.

It has been observed that the decay rate for proton emission from $d_{3/2}$ single particle state is systematically quenched compared with the prediction of a one-dimensional potential model although the same model successfully accounts for measured decay rates from $s_{1/2}$ and $h_{11/2}$ states. We reconcile this discrepancy by solving coupled-channels equations, taking into account couplings between the proton motion and vibrational excitations of a daughter nucleus. We apply the formalism to proton emitting nuclei ${}^{160,161}\mathrm{Re}$ to show that there is a certain range of parameter set of the excitation energy and the dynamical deformation parameter for the quadrupole phonon excitation which reproduces simultaneously the experimental decay rates from the ${2d}_{3/2},$ ${3s}_{1/2},$ and ${1h}_{11/2}$ states in these nuclei.

We analyze the effects of an in-medium broadening of nucleon resonances on the exclusive photoproduction of mesons on nuclei as well as on the total photoabsorption cross sections in a transport calculation. We show that the resonance widths observed in semi-inclusive photoproduction on nuclei are insensitive to an in-medium broadening of nucleon resonances. This is due to a simple effect: the sizable width of the nuclear surface and Fermi motion.

The $\mathrm{Li}{(}^7\mathrm{Li},$ ${}^{10}{\overrightarrow{{\mathrm{Be}}^{*}}}^4\mathrm{He}{+}^6\mathrm{He})$ reactions have been studied at bombarding energies of 34 and 50.9 MeV. For ${}^{10}{\mathrm{Be}}^{*}$ production near 0°, decay angular correlations are used to determine the previously unknown spin values and more accurate excitation energies of $J=2\mathrm{}$ at $E_x=9.56\mathrm{}\hspace{0.5em}\mathrm{MeV}$ and $J=3\mathrm{}$ at $E_x=10.15\mathrm{}\hspace{0.5em}\mathrm{MeV}.$ New excited states are proposed at higher excitations. A triaxial rotor model calculation and other collective rotation proposals all require a $J=4\mathrm{}$ state in the vicinity of 9 to 11 MeV, which has not been found. Angular correlation methods more general than have been used in the recent past are discussed.