The inner part of the Paris nucleon-antinucleon optical potential has been reanalyzed in view of new experimental constraints. These are mainly provided by accurate measurements of the analyzing power in charge-exchange scattering, p¯p→n¯n, together with elastic p¯p→p¯p polarization data, allowing a better determination of the isospin dependence of the short-range forces. The fit is performed with a set of 3632 data. The good quality of the fit is illustrated over a large sample of observables for laboratory momenta from 180 to 910 MeV/c. Curves of the potentials and of the phase shifts are shown as well as the parameters of the potentials and effective range formula coefficients for the S and P waves. The spectrum of resonances and bound states predicted by our potential is also displayed. In particular, a bound state having the AX(1565) quantum numbers is found with the right mass.

An energy-dependent and set of single-energy partial-wave analyses of NN elastic scattering data have been completed. The fit to 1.6 GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of πNN coupling constant. We also comment on the possibility of fitting np data alone. These results are compared with those found in the recent Nijmegen analyses.

We have studied the role of one- and two-pion exchange in the neutron-proton charge exchange cross section and spin-transfer variables. The cross section shows a scaling behavior over a wide energy range, consistent with a one-meson-exchange amplitude, and the spin-transfer observables are nearly invariant on a finite (but smaller) energy range. It is suggested that these data can be understood in terms of the exchange of pions between the quark constituents of the nucleon.

By calculating the contribution of the π-π three-body force to the three-nucleon binding energy in terms of the πN amplitude using perturbation theory, we are able to determine the contribution of the different πN partial waves to the three-nucleon force. The division of the πN amplitude into a pole and nonpole gives a unique procedure for the determination of the πNN form factor in the model. The total contribution of the three-body force to the binding energy of the triton is found to be very small.

We derive the dynamical equations which couple the four-body (πNNN) system to the underlying three-nucleon system. Our treatment can be considered the proper generalization of the Afnan-Blankleider equations for the coupled NN-πNN system. The resulting connected-kernel equations resemble in structure the Yakubovskiǐ-Grassberger-Sandhas equations for the standard four-body problem, but involve 24 chain-labeled components (rather than the usual 18 ones) and, within the scheme where the Hilbert space is truncated to states with at most one pion, allow for a consistent evaluation of reaction amplitudes involving π absorption/production.

Fine structure in the α decay of mass-separated ${}_{}{}^{186}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{184}{}_{}{}^{}\mathrm{Hg}$ has been studied at the GSI on-line mass separator. Alpha singles spectra as well as α-x-t and α-e-t coincidence events were collected. The α decay of ${}_{}{}^{186}{}_{}{}^{}\mathrm{Pb}$ revealed feeding to a low-lying $0^{+}$ state at 328(12) keV in ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hg}$. This state can be interpreted as being the bandhead of the deformed rotational band observed previously in in-beam studies. In the α decay of ${}_{}{}^{184}{}_{}{}^{}\mathrm{Hg}$, feeding towards the first excited $2^{+}$ state at 153 keV and the $0_2^{+}$ state at 478 keV in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Pt}$ was observed. The hindrance factor of the α decay towards the excited $0^{+}$ state gives information about the particle-hole character of the states connected in the α decay. A two-level mixing calculation is introduced. From the mixing in Pt and the α-decay hindrance factors, small mixing is deduced fro ground stattes of neutron-deficient Hg and Pb nuclei.

The results of a study of the compound nucleus ${}_{}{}^{114}{}_{}{}^{}\mathrm{Cd}$ by neutron time-of-flight spectroscopy methods are presented. Targets of both natural cadmium and cadmium enriched in the 113 isotope were used. The neutron total capture and neutron transmission were both measured. A total of 275 new resonances were located. In addition, 102 other resonances which were previously known but not assigned to a particular cadmium isotope were definitively assigned to ${}_{}{}^{113}{}_{}{}^{}\mathrm{Cd}$. Resonance parameters ${\mathit{E}}_0$ and g${\mathrm{\Gamma }}_{\mathit{n}}$ were obtained for both newly identified and previously known resonances. Of the 437 resonances now known in ${}_{}{}^{113}{}_{}{}^{}\mathrm{Cd}$, we identify 104 of them as l=1 based on their small widths. Strength functions and level spacings are obtained for both l=0 and l=1 resonances. Comparisons of the data with Porter-Thomas reduced width distributions, Wigner nearest neighbor spacing distributions, and the Dyson-Metha ${\mathrm{\Delta }}_3$ statistic are given. The linear correlation coefficient between adjacent spacings is also discussed. The spectroscopic information obtained is of importance for planning and interpretation of parity violation measurements on the p-wave resonances of ${}_{}{}^{113}{}_{}{}^{}\mathrm{Cd}$.

High-spin states in ${}_{}{}^{79}{}_{}{}^{}\mathrm{Kr}$ were studied using the ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$${(}^{18}$O,p3n) reaction at 65 MeV at the Florida State University Tandem-LINAC facility. Prompt γ-γ coincidences were observed using the Pitt-FSU detector array. Twelve new states were found, along with 19 new transitions. The yrast positive- and negative-parity bands were extended up to spins of (45/$2^{+}$) and (31/$2^{\mathrm{-}}$), respectively. Spin assignments were made based on directional correlation of oriented nuclei ratios whenever possible. A cranked-shell-model analysis shows some indication for a second band crossing in the positive-parity band at ħω≊0.75 MeV. This crossing, probably due to an aligned ${\mathit{g}}_{9/2}$ neutron pair, occurs with a much larger band interaction than the first ${\mathit{g}}_{9/2}$ proton crossing. An increase in signature splitting above ħω≊0.75 MeV and a return of large alternations in the B(M1)/B(E2) ratio is consistent with the theoretically predicted return to a nearly oblate shape.

It is observed that the even-even nuclei having identical ${\mathit{N}}_{\mathit{p}}$${\mathit{N}}_{\mathit{n}}$/Δ values exhibit identical excitation energies and/or energy ratios (${\mathit{E}}_{\mathit{J}}$/${\mathit{E}}_2$,${\mathit{E}}_{\mathit{J}}$/${\mathit{E}}_4$) in their ground-state bands (g.s.b.). ${\mathit{N}}_{\mathit{p}}$ (${\mathit{N}}_{\mathit{n}}$) is the valence proton (neutron) number and Δ is the average pairing gap, (${\mathrm{\Delta }}_{\mathit{p}}$+${\mathrm{\Delta }}_{\mathit{n}}$)/2. It is shown that this correlation is a manifestation of a very simple but uniform dependence of the excitation energies of the g.s.b. of even-even nuclei, spanning a wide mass region (70≤A≤244), on the ratio of their pairing and n-p interaction energies. An explicit form of this dependence is phenomenologically deduced and subsequently used to study the development of collectivity, existence of subshell closures and some other nuclear systematics.

The isovector giant resonances in heavy nuclei are considered. These excitations correspond to a gapless Goldstone mode which comes along due to the broken symmetry in the isospin space, and can exhibit themselves in a nucleus where the numbers of neutrons and protons are not equal. These modes can be interpreted as weakly damped fluctuations of the transverse isospin components, which propagate through the nuclear matter. The dispersion law of such isospin waves is calculated on the basis of the Fermi-liquid theory as well as by means of the semiclassical variational method. The finite size of the nuclei leads to quantization of the spectra and results in a series of excited states. The number of long-living excited states is strongly affected by the Landau damping. The orthogonality relations and energy-weighted sum rule are formulated. The collective isospin modes of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and other heavy nuclei are computed.

Quadrupole excitations in the nucleus ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ have been studied in a semiclassical framework using the nuclear Vlasov equation solved with the test particle method. A soft mode of quadrupole excitation located around 2 MeV is found. The strength (in percentage of the energy-weighted sum rule) exhausted in such a soft quadrupole excitation region is very sensitive to the extension of the neutron halo in the nucleus ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$. The results are discussed in comparison with other recent calculations. The use of the collective response to tune phase-space models of neutron excess nuclei to be used in collision dynamics is finally stressed.

Asymmetries of elastic electron scattering at low momentum transfer (q≤1 ${\mathrm{fm}}^{\mathrm{-}1}$) are used to study the difference of radii between neutron and proton distributions in nuclei such as Ca, Sn, and Ba isotopes. The asymmetry is shown to be another powerful tool to study the difference of neutron and proton distributions in nuclei.

We calculate the asymmetry in the missing-momentum distribution from the (e,e’p) reaction in a relativistic formalism. Longitudinal and transverse response functions are evaluated in parallel kinematics as a function of the three-momentum transfer to the nucleus. Analytic expressions for the responses are obtained in a relativistic plane-wave impulse approximation. These expressions reveal a large asymmetry in the momentum distribution, at the plane-wave level, induced by the lower components of the bound-state wave functions. These relativistic effects contaminate any attempt to infer color transparency from a measurement of the asymmetry in the (e,e’p) reaction.

A simple superfluid model with an effective four-body interaction of the monopole pairing type is used to explain the staggering of charge radii in the isotope chains. The contributions of deformation and of particle number projection are analyzed for the Sn isotopes. Good results are obtained for the staggering parameters and neutron pairing energies.

An effective two-body interaction is constructed from a new Reid-like NN potential for a large no-core space consisting of six major shells and is used to generate the shell-model properties for light nuclei from A=2 to 6. For practical reasons, the model space is partially truncated for A=6. Binding energies and other physical observables are calculated and they compare favorably with experiment.

We investigate the spin dependence of thermal properties and energy level densities of a deformed heavy nucleus in different microscopic treatments, which include a correlated approach based on a quadrupole interaction and the static path approximation, and a simple uncorrelated approach based on a deformed single particle Hamiltonian. Results in ${}_{}{}^{164}{}_{}{}^{}\mathrm{Er}$ are seen to exhibit similar characteristics in both approaches for not too high excitation energies, except for an almost constant enhancement factor in the level density. Level density parameters are also discussed.

A shell-correction method is applied to nuclei far from the beta stability line, and its suitability to describe effects of the particle continuum is discussed. The sensitivity of predicted locations of one- and two-particle drip lines to details of the macroscopic-microscopic model is analyzed.

The extended Wick’s theorem for fermion operators, which is used to compute matrix elements of an arbitrary operator between two different quasiparticle vacuums, is reformulated to deal with quasiparticle vacuums expanded in a finite single particle basis not closed under the canonical transformation relating them. A new expression for the overlap of those quasiparticle vacuums is also given.

The nucleon correlation including the short range correlation and the nuclear core polarization has been investigated by using a diagrammatic effective operator approach. The calculated results show that the contributions of the nucleon correlation to the the 0νββ decay of ${}_{}{}^{76}{}_{}{}^{}\mathrm{Ge}$ and ${}_{}{}^{82}{}_{}{}^{}\mathrm{Se}$ are quite important, especially in the heavy-neutrino case.

The moments of inertia of super-deformed nuclei in the Hg-Pb region are investigated. Deformation and pairing effects are treated self-consistently by means of the cranked Strutinsky Lipkin-Nogami approach. Special attention is drawn to the role of the quadrupole pairing force, which is crucial for the quantitative understanding of the moments of inertia, their dependence on N and Z, and hence the identical band phenomenon.